The books that you are planning to be selling for crypto, are they physical books or eBooks? And are you the one that’s writing these books or you’re getting them from somewhere else and then selling to those that needs it? I don’t think there is a demand for it, but one thing for sure is that it all depends on what you have in the book. If you are the type that writes what anyone can get for free online then no one will be willing to buy the book. You need to discover what people are looking for the most and then if you have the solution to that, you can write a book about it and I believe people would buy it.