[brudgers]

I love Lisp->crosswords idea.

SICP [2nd edition] is flat out just a more readable book than HtDP [first print edition, second edition is not in print but looks to be significantly improved].

As textbooks, it may be a bit of a different story, the tone of SICP is certainly cockier. There's less acknowledgement that mathematics is just domain knowledge within the context of an introductory "computer science" course. Then again, HtDP had two decades of experience with SICP upon which to draw. It also has the practical advantage of assuming that students had high levels of access to computers capable of running Lisp. That wasn't the case in the late 1970's and early 80's (or even the late 80's and mid 90's).