Perhaps better known as "The Polar Bear Book" from the cover design this classic book has just been published in a 3rd edition. The changes from the 2nd edition are more in the way of polishing than any attempt at a major revision though the new edition is some 40 pages longer. The chapter sequence and titles are virtually the same, and the additions and changes are mainly at a paragraph level. The chapter on search interfaces has been extended and the chapter on enterprise information architecture has been substantially revised. Virtually all the screen shots used as examples are taken from current sites and illustrate well the advances that have been made in IA thinking and practice since the 1st edition, for which the authors themselves should take a lot of credit.  

Some new topics have been included, such as tagging and folksonomies, though for some strange reason neither topic appears in the index. Equally perplexing is that there is no reference to the use of personas in IA development. The writing style is rather conversational, and that leads to some unusual sentence constructions and at least one sentence with 50 words. I got the feeling that authors Peter Morville and Lou Rosenfeld fitted the revisions in to a very busy business schedule. Although just occasionally it shows the IA community should be grateful they did find the time, energy and enthusiasm. Having just written a book myself (Making Search Work - due out in late March 2007) I know from personal experience what is involved.  

So should you buy the 3rd edition to replace which ever of the two previous editions you have? The answer has to be yes, especially at the (US) price of $39.95. Don't be put off by the subtitle of "Designing Large Scale Web Sites". That should have be been taken off the cover. The book is equally valuable to an intranet team, and the principles are just as important for small sites as large ones.  Since the 1st edition appeared in 1998 many other authors have gone into print on the subject of information architecture, but without doubt the 3rd edition will remain my first choice when I am looking for the sort of insights that Peter and Lou bring to this complex and challenging topic. The publisher is O'Reilly and the ISBN is 0-596-52734-9.