Zhou En Lai ‘s life is the history of modern China to 1970s. He was the eminence grise.
Some condemned him for failing to stop Mao from his crazy and reckless Cultural revolution and the Great Leap Forward. Most praised him for saving many lives behind the scene. Some he saved or helped were Deng Xiao Ping and Soong Ching Ling.
For a broad perspective here are 3 books.