Literate Programming and Lisp in Small Pieces

There have been various discussions of Literate Programming on HN, a technology Knuth said was one of his best ideas. The book "Lisp In Small Pieces" by Christian Queinnec is, in my opinion, the best example of a literate program available. The ideas are developed very, very carefully. The explanations in the paragraphs are clear and to-the-point. Actual code implementing the idea appears after each explanation, essentially using code like a physics book uses equations. Christian introduces ideas, like environment variables or continuations, in simple steps. He also discusses alternatives, their pros and cons. If you know of other literate programs please post a comment.