The Abelson and Sussman textbook, Structure and Interpretation of Computer Programs, uses LISP (actually Scheme). There are quite a few LISP fanatics who passionately feel it is still the best programming language made, citing such reasons as the simplicity of writing an interpreter for it. However, that textbook is pretty difficult. The authors didn't appreciate how hard recursion can be for many students to understand, and LISP and functional programming in general uses recursion so heavily it's the proverbial hammer for every nail of a programming problem.
Well, that's what you get when you beta test your textbook with MIT students. But that said, CLRS is no picnic for people who aren't very good at math, either.