No one reshaped Marxist-Leninist dogma as much as Mao Zedong, who led the communist takeover of China in 1949. And no one’s policies killed more of his own people, with estimates ranging from 20 to 40 million dead during Mao’s 27 years in power. Study the first half of his tumultuous reign, which saw China transformed in a bid to bring a sprawling peasant society into the modern industrial world.