I've read this cover to cover several times so thought I'd post a review.
I'd say it's the best book to get an overall view of Belgian beers and not just the Trappist beers it focuses on. It's a good one to start with if you want to get into brewing Belgian beers but have only previously done other styles. It's an engaging read that covers the principles and history behind the brews and how US brewers have made similar beers.
You don't get a lot in the way of recipes but you get a lot of helpful information about what's in the Trappist beers and how they make them. Information for some of them is limited but you get a few mash schedules, fermentation temperatures, malt bills, details of hops used and things like that. The book also looks at some non-trappist beers and breweries like Duvel, Caracole, Bink, DeKoninck and many more.
One thing I really liked was the table of different yeast strains from Wyeast and White Labs showing what flavours you can expect at different temperatures.
I've come back to this book again and again and I still find something new every time I look at it. Highly recommended.