To those who have a passing interest in Mexico and the Spanish conquest, this book cannot be too highly recommended. It is amazingly thorough, is based on incredibly wide-ranging research, and is written with an elegance and grace which belies the extraordinary welter of facts through which Thomas has to sift.
The character and personalities of all the various players come to the fore, and Thomas also does an excellent job of conveying the atmosphere of those times, as well as in adding little details like the weather and the scenery to give a real sense of what those terrible years were like.
In short, this is just a brilliant book - balanced, authoritative, erudite, and surprisingly moving - if you have any interest in Mexico you should read it. It is probably the best work of history that I have read.