I'd say HtDP is a good book for learning programming, but I don't think it's the best introduction to Racket. It also uses a specially crafted languages (a series of them) and focuses on the process of coming up and implementing the design, while removing most of the usual problems (cryptic error messages, too complex docs, too advanced techniques) which the beginners encounter. It's great as an introduction to programming, and it's even worthwhile a quick read for more experienced programmers (esp. self-taught), but it's definitely not about learning Racket, at all. The Little Schemer may be slightly better, but on its own, it too is not about learning Racket. Actually, I guess there's no book about Racket itself (EDIT: other than this one to some extent (in "explainers")) - existing books either focus on the basics of programming (HtDP, Realm of Racket) or on specific algorithmic problems and techniques (The X Schemer, SICP). Which is kind of natural given the educational background, but it makes it harder for already established programmers to learn Racket to get the job done.