Common Lisp for Schemers

What's the best way for a Schemer to learn Common Lisp? It seems like Scheme itself is a more beautiful language, but the efforts made by many implementations to make Scheme useful "in the real world" lead to a big ball of mud™. Does Common Lisp avoid this problem? Should I keep trying to learn different Scheme implementations instead until I find something I like?

>>1

A Schemer learns Common Lisp just like anyone else learns Common Lisp: Reading "Practical Common Lisp" and the Hyperspec, then supplementing that with practice and other books (I recommend PAIP).

When you learn Common Lisp, or any language for that matter, it is imperative that you do not compare it or look for similarities with other languages you know. Pretend you are learning your first language.

Only once you have mastered the langauge does it make sense to compare it with other languages you have mastered.