The central question which will be considered in this thesis is how Mao Zedong formulated a concept of imperialism and resistance to it, to enable and continue the socialist revolution in China. The specific focus in this thesis is an explanation of how Mao understood imperialism in order to use it and to turn it into anti-imperialism, the origins of his ideas, his theoretical development of it and his application of this idea in practice. At the same time, it will be examined how other aspects of Mao's thinking were linked to this central, strategic concept. The thesis begins by examining Mao's connection and indebtedness to Marx and Lenin: this has not yet been done with regard to his use of the concept of 'imperialism'. This thesis, besides being a contribution to the history of Marxism therefore, aims to fill a gap in research on Mao. It will help to establish how Mao used the concepts of imperialism and anti-imperialism. In addition, my research is part of the discussion as to what degree Marxism has been revised in the process. The argument essentially will be that Mao, basing himself on Marx and Lenin, used their concepts to adapt Marxism-Leninism in a novel manner in Chinese circumstances, first to win the revolution, and then to construct what he regarded as socialism. Thus the thesis will do two things: a) it will clarify Mao's relationship to Marx and Lenin: Why did Mao's Marxism-Leninism take the form it did. Did Mao stand on Lenin's shoulders.; and b) it will contribute to understanding why the Chinese Communist Party won the revolution.