Great book that has measured drawings of many master guitars. Unlike steel string guitars, where a few models dominate, and look different, say Gibson vs. dreadnaught martin, classical guitars look externally quite similar, while varying a lot internally, and otherwise. Many of the great artists of the steel string guitar play factory models, for a variety of reasons. Top classical guitarists largely play models that originated in small shops with one or a few craftsmen. For these reasons anyone who wants to make a study of building classical guitars will find this eclectic group of guitars very important.
However, one should consider:
The building instructions are 1) European in orientation, few jigs, open assembly and so forth, actually the best place for any guitarmaker to start, but not how most here do; 2) Weak in places, because the writer is not an expert guitar builder himself, though overall very helpful, and a useful reference.
The flip side of a great book on classic designs is that it isn't a good book on current designs. Guitar making theory has advanced somewhat (though one doubts the new instruments are better, they are nonetheless preferred by many anyway). Tone vs. durability or volume for instance. There has been a huge amount of new detail added to modern classicals, for instance work on intonation, volume, wolf notes, fingerboard playability, longevity, and so forth. this stuff isn't here, but on the other hand, it's plastered over the internet.
If you have seen the violin book, this one isn't the same. The violin book was partnered with a greatish builder. Deals a lot with modern practice (though being violins, that isn't that different anyway), and the violin book doesn't have lots of useful measured drawings (any in fact), because you can get patterns of the ouline parts for strads etc...
With whatever reservations, this is the greatest book on the classical guitar, and very reasonably priced, it used to sell for 100.