The book is very well illustrated with numerous photos and diagrams, and would be worth buying just for the photos alone.
The author is a retired professor of architecture from one of the leading universities in China (Tsinghua), and the book has the tone of the professor personally taking the reader on a guided tour of the architecture: where to look, what to see, the historical events that happened there.
The author fills in numerous insights, especially by comparing the architecture to its western equivalents. For example, why are Chinese cities formal and regularly planned, but their gardens informal and organic, while western cities are informal and organic, but western gardens are planned and formal? See page 187ff.
The one disagreement I would have is over the causes of the destruction of the old Summer Palace, which I suggest had more to do with the war aims of the British and French, rather than a simple desire for loot as the author implies (p217ff), (though British popular culture of the time did condone looting). But then this is a history of architecture, not of western imperialism.