I am a big fan of all of the Styles Series books, but this is by far my favorite. Nearly every brewing book covers British ales and continental lagers in detail, yet offer only the briefest of comments on Belgian ales.
Pierre Rajotte did extensive research for this highly readable book and he covers the history, styles and brewing techniques in just the right level of detail. Of particular value are his tips for working with high gravity beers.
If you brew and you love Belgian ales, I highly recommend this book.