[mojoe]

Happy to talk about it, the TL;DR is that this is a hobby where I as the editor don't expect to make back the money I spent creating the book, but the authors get paid a fixed amount up-front. Here's a more detailed answer: https://news.ycombinator.com/item?id=45785154#45879003

The only addendum to that answer is that after being featured on HN last week I'm now over halfway toward break-even.