What's On My Bookshelf
Practical Common Lisp. Peter Siebel. (2005, Apress). Written for Java/C++ programmers wanting to know about Lisp.
ANSI Common Lisp (Paul Graham 1996, Prentice Hall). Excellent instructive text for basic language features.
On Lisp, Advanced Techniques for Common Lisp (Paul Graham 1994, Prentice Hall). Excellent instructive text for advanced techniques.