A book that teaches about recursion. It introduces scheme, or at the very least, on an "idealized" version of scheme that only includes a tiny amount of procedure with which we can build on. It's a book that's written in a question and answer way, which I thought was strange as first, but grew to love. Another interesting fact about this book is that the author, Daniel Friedman, doesn't explicitly give formal definition. Instead, he shows examples and let the user form their own definitions, so that they are more sticky. Oh - and I got to say, I really enjoy the examples about food!