This essay attempts to briefly explore and to critically analyze Marx's basic ideas of political economy. As a trenchant attacker of capitalism and a severe critic of its theoretical defenders-the so-called classical political economists-, Marx traces out the main characteristics of the development of pre-capitalist and capitalist society. For him alienation and exploitation are two conspicuous phenomena which contrast the present system of capitalism to the former traditional society of feudalism and slavery. Through the publication of the Grundrisse in the 1930s and its English translation in the 1960s, the consistency of Marx's economic thought is reconfirmed and evident. Thus, the author endorses the viewpoint that despite periodization of the young and mature Marx, his economic thought is continuous and consistent throughout his lifetime. His basic idea is convoluted around the life-and-death struggle between labor and capital in philosophical terms of good and evil. His materialistic conception is a mythic vision in which the dualism of conflicting forces of the alienated self is apprehended as a dichotomy of social forces, a class struggle in society, a warfare of labor and capital. Marx's critique of political economy finally turns out to be a political, social and ethic theory of human fate.