This book is indeed a much needed and very welcome first one to cover all known species of reptiles from mainland SE Asia and the Greater Sundas.
All species are shown on color plates, with more detailed descriptions of their appearance, habitat, behavior and conservation status, distribution (without maps) to be found separately at the back of the book.
So far so good!
Unfortunately, while all this makes for a very interesting overview of the region's herpetofauna, the book's usefulness as an actual field guide is undermined by the fact that the illustrations are often too few, poor or inaccurate to let you identify even some very common species, and worse still, there are no keys provided to aid identification either.
For the Sunda subregion (Malay peninsula and the Greater Sundas), the more professionally compiled German language guide
Amphibien und Reptilien Südostasiens. can be much more useful, with keys and distribution maps, and quality photos of most species.