Describes macros well, has plenty of examples and very well written text, very well thought out text. This and ANSI Common Lisp complement one another very well. (I've heard Norvig's book is highly touted too, though I've not seen it in real life.)

I've studied a number of (computer) languages over the years, but one that I've never spent the time to really learn was Lisp. So, sitting down with this book one long weekend, I decided to give it a shot. What I found -- besides the fact that Lisp is a fascinating language that incorporates so many ideas that are only beginning to be incorporated in more "modern" languages -- is that Peter Seibel has written one of the best language tutorials that I have ever used. His style is conversational and clear, with the information broken up into easily digestible chunks. You may start this book thinking Lisp is just a hard-to-read language with too many parenthesis, but you will finish it with a new view of how computer languages should really work.

I found this to be an excellent book. Very helpful and practical. I found it complemented nicely the more theoretical "ANSI Common Lisp" book by Paul Graham.

If you've been using lisp for years already, the value of this book is probably more on the minimal side of things (although I suspect even a seasoned lisper might find it useful from time to time). However, if you're trying to get a grip on the ins and outs of coding in lisp, this book is a great place to begin. I find the book well-written and well-organized. Perhaps the biggest plus is that the book isn't overly 'dumbed down' and goes into sufficient depth to enable one to move beyond simple exercises at the REPL.

It is also nice to have a hard copy and the online version both available.

I tried more than one book to start learning CL, this one puts together the language principles with really well chosen code examples. The result is that I read it in a shot, with an increasing interest and never being intimidated.

After it I approached again the P. Graham's books and I finally found them really enjoyable.

The only critique I think is worth to be reported is about the software working environment. I tried lispbox on windows, but it is outdated, it is ok to try the companion source code downloaded from internet, but nothing more.
To start doing anything more serious I finally moved to linux, sbcl, emacs-cvs, and slime-cvs, it has been a pain. A few paragraphs on this topic would have been really helpful.

Anyway, it is a great reading! My gate to the Lisp world as a code writer instead of as a book reader.