This is a fascinating book, though written by a biased and unqualified author. Unfortunately, previous reviewer Allan Tong is way off the mark and unfortunately has no understanding of Chinese historiography. The book in question is certainly entertaining but to claim it contributes to our historical evaluation of Mao is a complete farce. If anything, Chang has done significant damage to the understanding of this complex figure, portraying him equally as one dimensional as any of his hagiographers. Those propping up this book as revealing do not realize it is more fiction than fact, and clearly know nothing about Chinese history. There are countless academic reviews of this book which have not only countered many of its most sensational claims but also questioned the authors' objectivity and dubious research. For instance, see academic reviews by Andrew Nathan (Columbia), Jonathan Spence (Yale), Perry Link (Princeton), or Steve Tsang (Oxford) among others. For an in-depth analysis, see The China Journal (55) where several scholars collaborated to provide a comprehensive look at the work. Even more recently, consult two new books: "The Battle for China's Past" (2008) by Mobo Gao or "Was Mao Really a Monster: The Academic Response to Chang and Halliday" (2009) edited by Gregor Benton.
As author Jonathan Fenby described in an article for the Guardian, "The central thrust of the book is that Mao was a sadistic monster, worse than Hitler or Stalin, and responsible for 70 million deaths. His Marxism was a shallow mask for selfishness. His reputation as a military leader and champion of the peasants was a sham, argue the book's authors. Portraying Mao as a creature of Stalin, the authors say that, far from moving China forward, he did nothing good, ruthlessly eliminating rivals, starving millions, provoking wars and treating his wives abominably." However, as described by Steve Tsang, "the methods used by the authors 'make for bad history and worse biography'." Another reviewer, Andrew Nathan wrote "that many of Chang and Halliday's claims are based on distorted, misleading or far-fetched use of evidence."
Ultimately, no historian will make use of the book, and professors will never consider using this material to teach students. This attempt at "Mao bashing" provides little to the body of work looking at one of the most important figures in the 20th century. Mao: The Unknown Story makes for an entertaining read, but this piece of "pseudo-history" is best ignored. If you are seriously interested in Mao or Chinese history, avoid this book like the plague. For a more balanced narrative, I would recommend Mao Zedong
by Jonathan Spence as a good introduction to the topic.