Donna Spencer (1)

A good book that gives exhaustive coverage of card sorting -- usually used for designing categories in web design and navigation. There's a good mix of theory and practical tips, with a number of real-life examples and stories.

The only book you'll ever need on card sorting: limited in scope but filled with pearls of wisdom.

If you haven't staged a card sort before then the first half of the book will steer you away from many of the common pitfalls that trap people the first time around. If you have then you won't find much new material here, but the book is an exhaustive compilation of the author's various published articles on the topic and a good point of reference.