The Other Lambda The Ultimate - Using the Y Combinator on Functions (twitter.com)

That was a really good book. This is good for learning LISP.

When you get the Y-Combinator function - it's quite a profound experience.

Steve Yegge wrote about learning LISP via this book. He said on a blog entry that he did every example in Scheme and Common LISP.

This is about one step away from implementing the eval function itself. Paul Graham did that in his "Roots of LISP" article.

I like how they pull it out step by step. The Y-Combinator just sort of falls out of the process.