Yes, "Why do you want to learn Lisp?" is a good question.
If the author wants to use Lisp because he/she thinks metaprogramming is interesting, or has read about the benefits of interactive programming, Common Lisp is the choice here.
If the author wants to use Lisp as a way to get a deeper understanding of important computer science topics, I think Scheme is the best choice and with this, following the SICP book.
If the author is interested specifically in functional programming and wants to get easy employment doing it, he/she should take a look at Clojure, Ocaml, and F#.
If the author wants to use Lisp because he/she thinks metaprogramming is interesting, or has read about the benefits of interactive programming, Common Lisp is the choice here.
If the author wants to use Lisp as a way to get a deeper understanding of important computer science topics, I think Scheme is the best choice and with this, following the SICP book.
If the author is interested specifically in functional programming and wants to get easy employment doing it, he/she should take a look at Clojure, Ocaml, and F#.