This is easily the best book on wine I have read, and if you also buy the World Wine Atlas, you may never need to purchase another book on the subject!
It is clearly aimed at the enthusiast or the professional though rather than the casual wine lover. It is a superb reference book, one to come back to again and again.
There is loads of regional detail, especially on the Old World, and excellent information on wine making and grape varieties. For an Italophile like me, its fantastic to have a fully comprehensive list of all DOC wines, and indigenous grapes for every region.
The only slight shortcoming is the overview of key producers for each region, which is fairly brief, and only really covers the main producers, not so much of the 'under the radar' small independents which can be such a joy to find. Best to seek out specialist merchants for those, though.
Overall, an essential volume for the serious wine enthusiast.