There's a couple samples out there,  most famously **Mastering Bitcoin** by Andreas M. Antonopoulos (https://github.com/bitcoinbook/bitcoinbook/). It's still for sale on Amazon, but also available on github.

I will soon set up a "donate" option, as soon as I figure that out... 

BitcoinHandsOn

bitcoin_beginners

This is why I wrote my book Bitcoin, Hands-On

Bitcoin demands constant learning if it intends to sustain itself. Of course, it's not just about writing down twelve words; those who say this want to summarize in a few words how easy it is to have your own money and save it. The nuances come when one delves deeper.

The idea of ​​an open-source book is interesting; I'd never seen it before.