The extent to which the Cultural Revolution has transformed the world-view of the Chinese masses remains among the psycho-cultural imponderables, but clearly it has revolutionized the western view of Chinese politics. The dominant pre-1966 image of a consensual solidarity disturbed only rarely by purges, also handled in an orderly way by a consensus excluding only its victims, was challenged by a sudden multitude of polemical claims to the effect that a struggle for power and principle had been raging behind the scenes for decades. This struggle was characterized as a “struggle between two lines”: a “proletarian revolutionary line,” led by Mao Tse-tung, and a “bourgeois reactionary line,” led by Liu Shao-ch'i and Teng Hsiaop'ing. This struggle allegedly represented a deep underlying ideological cleavage within the leadership that had repercussions on every aspect of Chinese life: foreign policy, strategies of economic development, techniques of leadership and administration, pay scales and living standards, delivery patterns for education, medicine, and other services; even scientific method. Allegations concerning this struggle were supported by a wealth of documentary evidence, culled from hitherto confidential Party and government files. Initially greeted with scepticism among western journalists and academic circles, some variant of the “two lines” paradigm has made increasing inroads into our attempts to understand the origins of the Cultural Revolution. The time has come to re-evaluate the conception of a two-line struggle in retrospect and to try to determine just what it means and how it functions.