The most entertaining way to get some sense of Chinese 19th C history: Flashman and the Dragon.
You can see where Mao came from. His horrors were just normal before him. Of course, this is historical fiction but Fraser tried to make it feel realistic. Sir Harry, I feel, was the original James Bond.
From Amazon:
Lusting after a clergyman’s wife, smuggling opium to Hong Kong, coupling with an Amazonian woman river pirate, groveling before a ruthless warlord, and becoming the sexual plaything of the most beautiful and evil woman in the world, Sir Harry Flashman, the supreme antihero of the Victorian era, is ready to rise to the occasion to matter what depths of dishonor he must plumb. In this uninhibited and uproarious adventure, Flashman is once again at his irascible best.