This is the first book I have ever taken the time to review, and the only book I have ever pre-ordered on Amazon. I usually wait for a few reviews to roll in before ordering a book, but I bought this one before the publication date based largely on the strength of Howell's other books. I'm happy to say this one is destined to be a classic, just like his other books. It does a masterful job balancing detail with big picture relevance, making it very accessible for the average birder, yet scholarly enough for a field ornithologist. You can use it as a reference book to look up details of molt in various bird families or species, or just sit down and read it cover-to-cover. It is definitely a great read, with a thorough and very interesting introduction on molt patterns and terminology, and very lucid descriptions of what once seemed like very confusing topics to me (such as stepwise wing molt).
The book is profusely illustrated with high quality photographs illustrating all the molt features discussed in the text. This greatly enhances the clarity of the points being made, and makes it much easier to go out and observe these features in the field.
The only minor criticism I have is with the slightly cumbersome referencing system. References are cited as superscript numbers in the text. Once you have the number, you go to the end of the chapter to get the author last name and year of publication, then you have to go to the bibliography at the end of the book to get the full reference. Most readers won't even notice it, but I'm a bit of a reference junkie. This minor issue is more than offset by a several things that enhance the quality and usefulness of the book. First, there are no typographical errors anywhere (at least that I could find in a normal careful reading). The page numbers and taxa being discussed appear on the lower corners of the pages, making it very easy to look things up or to just thumb through the book to find particular sections. And for the bibliophile, I'm happy to say the quality of the paper, printing, and binding is excellent.
This is definitely the most thorough, scholarly, yet completely accessible book on molt ever written and would be a worthy addition to any birder's library.