This book was one that bogged me down. Not because it is dull but because it is another REAL history book and it takes time and thought to read it. It is also an important book to understand where we are now in the world, despite the fact it takes place several hundred years ago. This is history for people who want to understand now.
We tend to think of the nation states as they exist now as monolithic things that existed, as is, since time immemorial, even when boundaries change within our own lifetimes. This book tells the story of Chinese, or more accurate, Manchu Quin Empire's, expansion at the expense of the Mongol people. The Chinese are not alone in this conquest/absorption. As they moved west, the Russian Empire was moving east. Caught in between were the Mongol people--specifically the Zunghar Mongols.
At the time these three groups played a game of cat and mouse that included diplomacy, duplicity and warfare.
Perdue meticulously catalogs the motivations of the players making clear that this wasn't "straight line" history. Nothing that happened was inevitable nor were the results all intended by the participants (certainly not the Mongols). Unlike the History of the Arab Peoples this book also gives glimpses of personalities and focuses on the motivation of the "great men" involved-- in some cases we know more about intentions because the men themselves wrote them down.
He also parses official histories an calls out the mistakes, omissions and lies. The end result of China's movement West was the creation of a multi-ethnic nation state that, more or less, exists today.
The book is exhaustive (and a little exhausting) but it is worth the time and effort. Keep in mind the effort isn't because it is written in a dry manner; it is actually quite engaging. It simply includes a vast amount of information.