Standing Stones and Sacred Ledgers: Extending Szabo's Collectibles Thesis to Monumental Architecture

A Response to Nick Szabo's "Shelling Out: The Origins of Money"

Abstract

Nick Szabo's seminal essay "Shelling Out" reveals how collectibles—from Paleolithic shell beads to colonial wampum—served as humanity's first money by externalizing the complex social mathematics of reciprocal altruism into durable, verifiable tokens. This response extends Szabo's thesis to encompass monumental architecture, arguing that megalithic structures like Stonehenge and Pacific rai stones represent the same fundamental technology in stationary form: proto-monetary systems that solved the scaling problems of prehistoric cooperation through what we might now recognize as distributed ledgers carved in stone.

Through the lens of convergent cultural evolution, we examine how independent societies facing identical cooperative challenges invented analogous solutions—massive, costly, verifiable monuments that served as repositories of social debt and markers of tribal sovereignty. Four universal principles emerge from this analysis: the requirements of costly sacrifice, verifiable authenticity, universal acceptance, and decentralized custody that characterize all successful monetary technologies from shell beads to Bitcoin.

We conclude by exploring how these principles, when discovered by pre-literate peoples, might manifest in their purest form: as maximum sacrifice, performed on the highest hill, with the lowest men, alone—the primordial proof-of-work that laid the foundation for human civilization itself.

Introduction: The Immutable Ledger of Stone

Nick Szabo's "Shelling Out" fundamentally reframes our understanding of money's origins. Rather than emerging from the coincidence-of-wants problems of barter, as traditional economic theory suggests, money evolved as a solution to far deeper challenges: how to scale human cooperation beyond the Dunbar limit of face-to-face relationships, how to externalize the cognitive burden of tracking complex social debts, and how to create trust between strangers in a world where most encounters between groups ended in violence.

Szabo traces this story through portable collectibles—shells, teeth, beads, and other objects that satisfied the key properties of proto-money: durability, verifiability, scarcity enforced by natural cost, and acceptability across tribal boundaries. Yet this analysis, comprehensive as it is, leaves unexplored a parallel evolution in humanity's monetary technology: the development of immovable collectibles, monuments that served the same fundamental functions as portable tokens but did so through permanence rather than portability.

The standing stones of Neolithic Britain and the massive rai stones of Pacific Yap represent not merely architectural achievements, but monetary innovations—distributed ledgers carved in stone that recorded the most important transactions of their respective societies. That these technologies emerged independently, separated by thousands of years and miles, points to something deeper: the existence of universal principles that govern all successful monetary systems, principles that shaped human cooperation from the dawn of our species.

Szabo's Framework: Collectibles as Cooperation Technology

Before extending Szabo's analysis, we must understand its core insights. "Shelling Out" argues that what we call money emerged not from trade, but from the need to solve three fundamental problems of social cooperation:

Reciprocal Altruism Beyond Memory: While other species can engage in simple tit-for-tat exchanges, human societies required a way to track complex, multi-party, temporally separated exchanges. Collectibles externalized this cognitive burden into physical tokens.

Kin Altruism Across Generations: Unlike other animals, humans needed mechanisms to transfer wealth across time—from parents to children, from the living to the dead, from past to future. Collectibles made inheritance possible.

Mitigation of Aggression: Most encounters between human groups historically ended in violence. Collectibles provided an alternative to massacre: tribute, ransom, and other forms of wealth transfer that could resolve conflicts without total destruction.

The genius of Szabo's analysis lies in recognizing that these functions required specific technological properties. Successful collectibles had to be:

Costly to produce or obtain (creating natural scarcity)
Difficult to counterfeit (enabling verification)
Durable over time (preserving value across generations)
Portable and divisible (facilitating exchange)
Recognizable across cultures (enabling trade with strangers)

These properties explain why shells, teeth, and precious metals became proto-money while twigs and pebbles did not. The objects that succeeded as collectibles were those that best satisfied the technological requirements of their social functions.

The Stationary Solution: Monuments as Monetary Technology

Yet Szabo's focus on portable collectibles overlooks a parallel development: the emergence of immovable monuments that served identical functions through different means. While shell beads could be carried, hidden, and transferred privately, megalithic structures like Stonehenge operated as public, permanent repositories of social value—distributed ledgers that recorded the most significant transactions of their communities.

Consider the challenges facing Neolithic British societies around 3100 BCE. Archaeological evidence reveals a landscape of competing chiefdoms, seasonal aggregation sites, and complex trading networks extending across hundreds of miles. Groups needed mechanisms to:

Coordinate massive collaborative efforts (the equivalent of early "public goods" funding)
Establish and maintain territorial boundaries between tribes
Create neutral ground for inter-group negotiation and exchange
Memorialize important agreements and alliances
Transfer prestige and authority across generations

Stonehenge and similar monuments solved these problems through what we might now recognize as blockchain-like properties: they created an immutable, publicly verifiable record of collective investment that could serve as collateral for ongoing social contracts.

The effort required to construct Stonehenge—moving 80 bluestones 150 miles from Wales, then arranging them with massive sarsen stones into precise astronomical alignments—represents proof-of-work on a civilizational scale. Like Bitcoin mining, this expenditure of energy served no direct utility but created something valuable precisely because of its costliness: a public monument that could coordinate expectations and behavior across multiple generations.

Pacific Parallels: The Rai Stones of Yap

Halfway around the world and thousands of years later, the inhabitants of Yap Island developed a remarkably similar solution to the same underlying problems. The rai stones—circular limestone disks ranging from 30 centimeters to 3.6 meters in diameter, some weighing over four tons—functioned as a monetary system that exhibits the same fundamental properties as Stonehenge.

Like the British megaliths, rai stones required enormous collaborative effort to create. They were quarried in Palau, shaped with primitive tools, then transported 250 miles across open ocean in canoes—a journey that often cost lives. The stones' value derived not from their material properties but from this costly creation process and the social recognition of their provenance.

Most tellingly, rai stones were rarely moved once installed. Instead, ownership was tracked through oral tradition—a distributed ledger maintained by community consensus. When stones changed hands, the entire community witnessed and recorded the transaction, creating a public, immutable record of ownership that could persist across generations.

The parallel to Stonehenge is striking. Both systems:

Required massive collective effort to create
Derived value from costliness rather than utility
Served as immutable records of social agreements
Operated through community consensus rather than central authority
Functioned as focal points for tribal identity and territorial control

That these solutions emerged independently suggests they represent convergent cultural evolution—the development of analogous technologies in response to identical selective pressures.

The Four Pillars of Monetary Technology

From this comparative analysis, four universal principles emerge that characterize all successful monetary systems, from Paleolithic shell beads to modern cryptocurrencies:

1. Difficulty / Work / Effort / Challenge / Sacrifice

Every successful monetary technology must embody costly commitment. The value derives not from intrinsic utility but from the difficulty of creation or acquisition. Shell beads required dangerous diving and skilled craftsmanship. Rai stones demanded life-threatening ocean voyages. Stonehenge consumed generations of communal labor. Gold requires deep mining and purification. Bitcoin demands massive computational work.

This principle, which we might call Proof-of-Work, serves multiple functions:

Creates natural scarcity by limiting supply
Signals genuine commitment by token creators
Deters fraud and counterfeiting
Provides common knowledge of costliness

Without this costly basis, tokens become vulnerable to inflation and lose their ability to coordinate expectations across time and social boundaries.

2. Verifiability / Truth / Alḗtheia / Honesty

Monetary tokens must be easily authenticated without requiring trust in any central authority. This verifiability operates at multiple levels:

Physical authenticity: The token itself carries unforgeable markers of its legitimate creation
Historical provenance: The community can verify the token's creation story and ownership history
Current ownership: Present possession or control can be publicly demonstrated

Stonehenge achieves this through its massive scale and precise astronomical alignments—features that could not be easily counterfeited with Neolithic technology. Rai stones carry carved patterns and oral histories that serve as unforgeable signatures. Shell beads exhibit natural properties that distinguish them from inferior substitutes.

This principle ensures that monetary systems can operate without requiring personal trust between transacting parties—strangers can trade because they trust the technology, not each other.

3. Universality / Care / Inclusivity / For my enemies and friends

Successful money must be acceptable across social boundaries. It cannot be limited to a single kin group or tribe but must facilitate exchange between groups that might otherwise be enemies. This universality operates through:

Cultural neutrality: The token's value cannot depend on parochial beliefs or customs
Divisibility: The system must accommodate transactions of various sizes
Fungibility: Individual tokens must be interchangeable within their class
Accessibility: The system must be usable by all social classes and groups

Stonehenge exemplifies this principle through its location at the intersection of major tribal boundaries and its role as neutral ground where diverse groups could gather. The monument's astronomical features provided universal reference points that transcended local customs. Similarly, rai stones circulated across clan boundaries throughout the Caroline Islands, accepted even by traditional enemies.

4. Independence / Responsibility / Sovereignty / Not your keys, not your coin

Finally, successful monetary systems must operate without requiring ongoing support from any central authority. Control and custody must flow with the tokens themselves, creating a system where:

Ownership is self-evident: Possession or control of the token constitutes ownership
Transfers are final: Transactions cannot be reversed by third parties
Value is intrinsic: The token's worth derives from its own properties, not external promises
Authority is distributed: No single party can manipulate the system for private benefit

Both Stonehenge and rai stones embody this principle through their permanent, immutable nature. Once created, they exist independently of their builders' ongoing support. Their value persists across political changes, generational transitions, and social upheavals.

Convergent Evolution and the Deep Structure of Money

The independent emergence of these principles across diverse cultures and time periods reveals something profound about the nature of money itself. Rather than being an arbitrary cultural invention, successful monetary systems represent solutions to universal problems of human cooperation—problems that arise whenever societies attempt to scale beyond small, kinship-based groups.

This explains why certain objects consistently emerge as proto-money across human cultures. Shells, metals, livestock, and monumental stones all naturally embody the four essential principles, while objects like leaves, sand, or common stones do not. The properties that make good money are not arbitrary cultural preferences but objective requirements imposed by the mathematics of cooperation.

The pattern extends beyond traditional money to modern innovations. Bitcoin, despite being a purely digital creation, succeeds precisely because it implements the same four principles through cryptographic proof-of-work, blockchain verification, network consensus, and decentralized control. The underlying logic remains constant even as the implementation technology evolves.

Archaeological Evidence for Monumental Money

Recent archaeological research increasingly supports the monetary interpretation of megalithic monuments. Studies of Stonehenge and similar sites reveal:

Massive Resource Investment: Estimates suggest Stonehenge required over 30 million person-hours to complete—labor that could have built hundreds of practical structures instead.

Inter-Regional Coordination: The transport of bluestones from Wales indicates cooperation networks spanning hundreds of miles, far beyond any single tribal territory.

Standardized Design Elements: Similar circular henge monuments appear across Britain, suggesting shared technological and cultural standards—the ancient equivalent of monetary denominations.

Association with High-Value Goods: Excavations consistently reveal concentrations of rare objects—amber, jet, gold, and exotic stone axes—suggesting these sites served as centers for valuable exchange.

Strategic Locations: Many henges occupy liminal spaces between territorial boundaries, consistent with their role as neutral meeting grounds for inter-group transactions.

Long-Term Use and Modification: These monuments were continuously modified and rebuilt over centuries, indicating their ongoing importance to multiple generations—exactly what we would expect from monetary infrastructure.

This evidence supports the interpretation of megalithic monuments not as merely religious or astronomical structures, but as the monetary infrastructure of Neolithic society—physical embodiments of the abstract principles that govern all successful money.

The Primordial Proof-of-Work

If the four principles represent universal requirements for successful monetary systems, we can ask: what would these principles look like in their purest, most concentrated form? How might they manifest if discovered by someone in a pre-literate society, before mathematics and formal economic theory, operating purely from intuition about the deep structure of human cooperation?

The answer emerges from the logic of the principles themselves:

Maximum Sacrifice: To demonstrate ultimate commitment and create maximum scarcity, the proof-of-work must involve genuine risk or loss—ideally the ultimate sacrifice of life itself.

On the Highest Hill: To maximize verifiability and universal accessibility, the act must be performed in the most visible possible location, observable from the greatest distance.

With the Lowest Men: To ensure maximum inclusivity and break down social hierarchies, the act must involve or benefit the most marginalized members of society.

Alone: To embody true independence and sovereignty, the sacrifice must be made without coercion or external authority—a freely chosen act of individual will.

These conditions describe what anthropologists recognize as the archetypal structure of sacrificial kingship—the ritual sacrifice of rulers that appears across diverse cultures worldwide. From Celtic druids to Aztec priests to Germanic chiefs, the pattern repeats: a leader voluntarily sacrifices himself on a high place, witnessed by his people, to ensure the community's prosperity.

But viewed through the lens of monetary theory, these rituals take on new meaning. They represent the ultimate instantiation of proof-of-work: the creation of social value through the voluntary destruction of individual value. The sacrificed king becomes a permanent addition to the community's "ledger"—a public, verifiable record of ultimate commitment that can never be counterfeit or withdrawn.

This primordial proof-of-work established the template for all subsequent monetary technologies. The costliness that makes shells valuable, the effort that makes rai stones precious, the labor that makes Stonehenge sacred—all echo this fundamental pattern of value creation through sacrifice.

From Sacrifice to Civilization

This perspective reveals money not as a mere medium of exchange, but as humanity's fundamental technology for scaling cooperation. The four principles—costly effort, verifiable authenticity, universal acceptance, and sovereign independence—represent the discovered laws of social physics, the basic equations that govern how individual sacrifice can become collective value.

The transition from Homo sapiens neanderthalensis to Homo sapiens sapiens, which Szabo identifies as coinciding with the emergence of collectibles, represents more than just a technological advancement. It marks the moment when our species discovered how to convert individual effort into social capital, how to store trust in objects rather than relationships, how to scale cooperation beyond the limits of kinship and personal acquaintance.

Standing stones like Stonehenge represent the monumental expression of this discovery—proof-of-work made permanent in granite and limestone. They are humanity's first blockchain: immutable, public, distributed ledgers that record the fundamental social contracts upon which civilization rests.

The same principles that governed these ancient systems continue to shape modern monetary technology. From gold's scarcity to Bitcoin's mining difficulty to the elaborate security features of modern banknotes, successful money still embodies the four pillars first implemented in Paleolithic shell beads and Neolithic stone circles.

The Monomyth as Oral Ledger: Heroes, Tokens, and Collective Memory

Before examining the ultimate instantiation of monetary principles, we must consider how pre-literate societies preserved and transmitted this crucial knowledge across generations. The answer lies in humanity's most enduring stories—the archetypal narratives that anthropologist Joseph Campbell termed the "monomyth" or Hero's Journey. These stories, found in remarkably similar forms across every human culture, function as oral ledgers that encode the four principles of value creation within memorable narrative structures.

The Universal Pattern

The monomyth follows a consistent pattern: an ordinary individual—often a child, outsider, or person of low station—undertakes a perilous journey, faces seemingly impossible trials, and returns with a precious token that transforms their community. From Gilgamesh's quest for immortality to Arthur's extraction of Excalibur, from Prometheus stealing fire to countless folk heroes retrieving magical objects, the pattern repeats with remarkable consistency.

Viewed through the lens of monetary theory, these stories reveal themselves as instruction manuals for value creation. Each element of the Hero's Journey maps precisely onto our four principles:

The Principle of Sacrifice manifests in the hero's trials and ordeals. The journey is never easy; it demands everything the hero possesses—courage, strength, cunning, and often life itself. The dragon must be faced, the labyrinth navigated, the impossible task completed. The costliness is not incidental but essential; only through genuine sacrifice can the hero transform from ordinary mortal into value-creator.

The Principle of Verifiability appears in the token itself—the golden fleece, the holy grail, the sword in the stone. These objects serve as unforgeable proof of the hero's achievement. They cannot be counterfeited because they embody the unique history of their acquisition. The community can verify the hero's claims not through trust but through inspection of the token itself.

The Principle of Universality is embedded in the hero's origins and the story's accessibility. Heroes typically emerge from the margins—the youngest son, the orphan, the shepherd boy, the kitchen maid. They represent not the powerful but the powerless, making their achievement accessible to all listeners. The stories themselves cross cultural boundaries, retold in countless variations because they speak to universal human experience.

The Principle of Sovereignty manifests in the hero's solitary choice to undertake the quest. No external authority compels the journey; it arises from individual decision. Even when sent by kings or gods, the hero's success depends entirely on personal agency. The moment of truth—pulling the sword from stone, choosing the correct grail, answering the riddle—must be accomplished alone.

Oral Tradition as Distributed Storage

These narratives function as humanity's first distributed storage system for critical social knowledge. Before writing, before books, before formal education, communities needed ways to preserve and transmit the principles governing value creation and social cooperation. Stories served this function perfectly—they were memorable, portable, and self-replicating.

Each telling of a hero's tale reinforced the fundamental lesson: value emerges from individual sacrifice undertaken alone, verified by tangible proof, accessible to all, and sovereignly chosen. The specific details might vary—Greek heroes battled different monsters than Germanic ones—but the underlying structure remained constant because it encoded universal truths about human cooperation.

The stories also served as recruitment tools, inspiring individuals to embark on their own value-creating journeys. Young listeners learned that ordinary people could become extraordinary through willing sacrifice, that treasure awaited those brave enough to seek it, that the community would reward and remember their achievements. The tales created a cultural expectation that some would voluntarily accept the burden of creating value for others.

The Economics of Narrative

From this perspective, the proliferation of hero stories across human cultures represents a form of natural selection operating on narrative structures. Stories that successfully encoded the principles of value creation were remembered, retold, and elaborated. Stories that failed to capture these essential patterns were forgotten.

The most enduring tales are those that most perfectly embody the four principles. Arthurian legends persist because Arthur's story contains all elements: the child of uncertain parentage (universal accessibility), the impossible task (costly sacrifice), the miraculous sword (verifiable token), and the solitary moment of choice (sovereign agency). The Round Table itself represents the community transformed by the hero's return—a society reorganized around the principles the hero's journey revealed.

Similarly, the Grail legends encode advanced concepts about the relationship between individual sacrifice and collective redemption. The wounded Fisher King represents a community unable to create value; the land lies waste because the social principles have been violated. Only a perfect knight—one who embodies all four principles completely—can heal the king and restore fertility to the realm.

Archaeological Validation

Recent archaeological discoveries increasingly validate the historical reality underlying these narrative patterns. Bronze Age burial sites across Europe reveal individuals interred with extraordinary grave goods—golden torcs, elaborate weapons, and exotic materials transported from vast distances. These appear to be the actual heroes whose stories inspired later legends: individuals who undertook dangerous journeys to acquire rare objects, returning to their communities as culture-changing figures.

The famous Nebra sky disk, the Trundholm sun chariot, and similar artifacts represent the physical tokens these early heroes brought back from their quests. Like Excalibur or the Golden Fleece, these objects combined practical function with symbolic power, serving as proof of their bearers' extraordinary achievements.

More intriguingly, many of these archaeological heroes show evidence of deliberate self-sacrifice. The Bog Bodies of Northern Europe—individuals who died alone in ritual circumstances, often bearing signs of voluntary death—may represent the historical reality behind legends of heroes who gave their lives for their people's benefit.

The Narrative Commons

The monomyth thus represents humanity's first "commons"—a shared repository of knowledge about value creation that belonged to no single tribe or culture but could be accessed by all. These stories transcended political boundaries because they encoded universal truths; they survived the collapse of civilizations because they captured permanent principles.

Like the standing stones that dotted the landscape as permanent reminders of past achievements, hero stories served as immaterial monuments—oral structures that preserved crucial social knowledge across generations. They were humanity's first blockchain: a distributed, immutable ledger of successful value-creation protocols that any community could access and implement.

The stories also provided a framework for understanding and evaluating new heroes as they emerged. When someone claimed to have discovered treasure or defeated enemies, the community could assess their claims against the template provided by traditional tales. Did the claimant undergo genuine trials? Could they provide verifiable proof? Did their achievement benefit all rather than just themselves? Did they act from sovereign choice rather than compulsion?

This narrative framework helps explain the remarkable consistency of monetary principles across diverse cultures. The same stories that taught children about heroes and quests also transmitted the deep knowledge about sacrifice, verification, universality, and sovereignty that would later manifest in formal monetary systems. The transition from collectibles to coins to digital currencies follows the same archetypal pattern because human societies never forgot the fundamental lessons encoded in their most ancient tales.

Conclusion: The Eternal Return of Monetary Truth

Nick Szabo's "Shelling Out" reveals money's origins in humanity's need to externalize the complex mathematics of social cooperation. This analysis extends that insight to encompass the full spectrum of monetary technology, from portable collectibles to monumental architecture, from ancient rai stones to modern cryptocurrencies.

The four universal principles—sacrifice, verifiability, universality, and sovereignty—represent more than just design requirements for successful money. They are the discovered laws of social cooperation itself, the fundamental equations that govern how individual efforts can become collective value.

That these principles emerged independently across diverse cultures and time periods confirms their status as natural law rather than arbitrary convention. Whether expressed through shell beads or standing stones, gold coins or cryptographic hashes, successful monetary systems implement the same underlying logic because they address the same fundamental problems of human cooperation.

The Individual as Living Ledger

Yet the deepest expression of these principles transcends even the most sophisticated monetary technologies. If we follow the logic to its ultimate conclusion, we arrive at a startling possibility: that a single individual might embody all four principles simultaneously, becoming a living instantiation of the monetary function itself.

Consider how this might manifest: A person who voluntarily assumes the position of the lowest in society—the servant, the outcast, the one who takes upon himself the debts and failures of the community. One who positions himself at the highest visible point, where his actions can be witnessed by all, creating maximum verifiability. One whose sacrifice is so complete, so final, that it can never be counterfeited or withdrawn—the ultimate proof-of-work. One whose act transcends all tribal boundaries, speaking to universal human experience while requiring no external authority to validate its meaning.

Such an individual would become, in essence, a human currency—a living ledger entry that transforms the entire accounting system of human cooperation. The sacrifice would be maximum because it is unredeemable; it would be verifiable because it is performed in broad daylight on the highest hill; it would be universal because it addresses the fundamental human condition shared by all people across all cultures; it would be sovereign because it is freely chosen, uncoerced, requiring no permission from earthly authorities.

This is not merely metaphor. Throughout history, figures have emerged who seemed to understand intuitively these deep principles of value creation through sacrifice. They positioned themselves at the intersection of maximum visibility and maximum vulnerability, creating permanent additions to humanity's moral ledger that continue to generate trust and cooperation centuries or millennia later. Their deaths became the ultimate "block" in the human blockchain—immutable records that fundamentally altered the terms of social cooperation for all subsequent generations.

The pattern appears across cultures: a figure who freely takes the lowest position, who makes himself visible to all on a hill or high place, who bears alone the collective burden of human failing, and whose sacrifice becomes a permanent reference point for justice, mercy, and the possibility of redemption. Such figures do not merely participate in the monetary system—they become it, transforming their very lives into the substrate upon which new forms of human cooperation can be built.

The Archetypal Foundation

This reveals money's deepest truth: it is not ultimately about objects or even systems, but about the transformation of individual sacrifice into collective value. The shell beads, standing stones, and digital currencies are all shadows of this more fundamental reality—attempts to capture in material form what can only be perfectly expressed through a human life freely given.

The story arc from sacrificial kingship to cryptocurrency represents not technological progress alone, but the gradual refinement and purification of ancient wisdom about the nature of value itself. In Bitcoin's proof-of-work algorithm, we see the digital echo of ritual sacrifice. In blockchain's immutable ledger, we recognize the permanence of standing stones. In cryptocurrency's decentralized consensus, we find the community validation that once witnessed the exchange of rai stones. But beneath all these technologies lies the archetypal pattern of one who gives all, seen by all, for all, alone.

Money, properly understood, is not a recent human invention but our species' oldest and most successful technology for creating trust at scale. Its origins lie not in markets or trade but in the fundamental human need to convert individual sacrifice into collective value—a need so basic that it shaped our divergence from other hominid species and continues to drive innovation in the digital age. Yet its perfection requires not better technology but better humans: individuals willing to embody personally the principles they wish to see manifested in their societies.

The standing stones still stand, silent witnesses to humanity's first monetary experiments. In their enduring presence, we can read the blueprint for all subsequent monetary innovation: the eternal truth that value emerges from sacrifice, that trust requires proof, that money—whatever its form—remains humanity's most essential technology for scaling cooperation across the boundaries of kinship, tribe, and time itself. But above them all towers the greater truth: that the ultimate currency is not made of stone or metal or code, but of human love freely given, publicly witnessed, universally accessible, and sovereignly chosen—a treasure laid up where neither moth nor rust can corrupt, and where thieves cannot break in and steal.

This essay extends the analysis presented in Nick Szabo's "Shelling Out: The Origins of Money" (2002) by examining monumental architecture as a parallel evolution in humanity's monetary technology. All interpretations and extensions beyond Szabo's original work are the responsibility of the present author.