(note: this review is of the original, 1980 edition)
Lives up to the title in that it explains Mao and only Mao -- nothing about historical context or the people that Mao encountered, and ridden with cliches.
Examples:
"All through history the semi-intellectual has been the most potent person in an inchoate political situation."
How? Any examples besides Mao? What exactly defines a semi-intellectual?
"The results were disastrous. Battles were lost. Troops deserted. Towns that had been held by the reds fell to the enemy."
What battles were lost? Why were they lost? Why did troops desert?
"Two men set out with the precious bottles; one was beheaded en route, one got through."
A man is beheaded and you're not going to tell me why? You won't even explain what the hell it is about China in the early 1900s that allows people to be beheaded while carrying precious bottles?
Most egregiously, at age 14 Mao is arranged to be married to a woman 6 years his senior. But we never hear anything about what becomes of this wife, if they divorced, how Mao treated her, and so forth.
Terrill's book was published in 1980, only four years after Mao's death. One gets the idea Terrill can't be blamed for this book's errors (which are legion) is left to wonder if everything feels so haphazard because of publisher pressure to beat other Mao bios. Find a later edition by a different author; this one went obsolete the day it was published.