'(Montreal Scheme/Lisp User Group)

Structure and Interpretation of Computer Programs (SICP) by Abelson and Sussman. The Bible.
Lisp in Small Pieces (L.i.S.P.) by Christian Queinnec. Greatest book on the implementation of Lisp-like languages. A french version is also available.
Practical Common Lisp by Peter Seibel. One of the best books on Common Lisp.
Successful Lisp by David B. Lamkins. Another nice book on Common Lisp.
On Lisp by Paul Graham. A must read!
Ansi Common Lisp by Paul Graham.
Paradigms of Artificial Intelligence Programming: Case Studies in Common Lisp by Peter Norvig. One of the best programming book ever!
Other books can be found on the Schemers.org web site.