An overview of why programmers use Lisp
An overview of the technical features of Lisp
External Publications and Books
A nice online introduction to Lisp, with many links to other resources.
A highly readable introduction to Lisp. The first two chapters, enough to get you started writing programs, are online. The book is available to buy.
Recommended for beginners and experienced programmers alike. A direct approach with plenty of modern examples. Available as a book or online.