Practical Common Lisp is very good and it's free: http://www.gigamonkeys.com/book/ http://www.gigamonkeys.com/book/ For more advanced stuff, On Lisp and Let Ov

Practical Common Lisp is very good and it's free: http://www.gigamonkeys.com/book/ http://www.gigamonkeys.com/book/ For more advanced stuff, On Lisp and Let Over Lambda are both good, and both (mostly) free.