In this greatly expanded second edition, six completely new chapters cover the Common Lisp Object System (CLOS), conditions, Pretty Printing, Loops, Series, and Generators. All of the new material -- well over half the book -- is clearly distinguished from the original text. It reflects changes or potential changes to the language resulting from some 185 votes of the ANSI committee on standardizing Common Lisp. It includes as well fresh examples and additional clarifications, warnings, and tips -- all presented with the author's customary vigor and wit.
Guy Steele has a talent for making something like a programming language spec interesting and easy to read. The information in this book is freely available online, but I collect older technical books just to keep around for the times I want to flip through them. The paperback is short and thick, but is pretty good quality, and worth looking for if you're into books of this nature.