A short piece by Mises, "Economic Calculation in the Socialist Commonwealth", helped me better understand the following ideas and how they relate to eachother: free markets, economic calculation and price formation.

I also remember reading "Bureaucracy" by Mises and it helping me understand free markets, how they work, what incentives are present, what kinds of results they tend to produce etc by contrasting it to a very different way of allocating resources namely bureaucracy. That piece is not quite as short as the first I mentioned but still not that long.