Mao Zedong (b. 1893–d. 1976) was one of the most remarkable political leaders of the 20th century, an all-powerful leader in China, and a major world figure. His career as a Communist revolutionary lasted fifty-five years. Half this time was spent in revolutionary struggle, and half, after the establishment of the People’s Republic of China in 1949, in the struggle to build a revolutionary state. Mao’s rise to leadership was gradual: starting as an obscure Communist Party functionary, he was in turn a labor organizer, a guerrilla commander, and a leader in the Communist base areas before finally becoming chairman of the party in 1943. As the unchallenged leader of the new People’s Republic of China in 1949, with his colleagues Mao began the revolutionary transformation of China through land reform, collectivization, industrialization, and the comprehensive politicization of daily life. Under Mao’s leadership the country was unified and began a process of modernization and industrialization that would allow it to become a major power after his death. However, within a few years of taking power, Mao began to suspect his colleagues of backsliding and refusing to recognize the danger to socialism that he believed a new elite would pose. His disputes with them convulsed China and dominated the last twenty years of his life. His efforts to achieve his vision of a China that was both egalitarian and prosperous failed and ultimately visited enormous suffering on his people. Moreover, his ruthlessness toward his opponents and his cynical exploitation of his cult of personality during the Cultural Revolution disillusioned many of his followers. His successors reversed Mao’s policies, seeking a new legitimacy for the party state in improved standards of living, achieved through a return to a marketized economy. Mao’s life and record still spark great interest inside and outside China. The large and growing literature on Mao covered in this article includes biographies, monographs on almost every aspect of his life and work, assessments of his legacy, and multivolume editions of his writing. Mao scholars struggle to come to terms with his legacy. He has been portrayed by some as China’s redeemer and by others, as a monster. Chinese appraisals are inevitably affected by the official line that he was a great revolutionary leader who made very serious errors. Late-20th- and early-21st-century Western scholarship tends to insist on Mao’s complexity and his many dimensions.