The following excerpt from Marx’s preface to his A Contribution to the Critique of Political Economy (1859) provides a particularly clear and succinct account of what Marx meant by “the materialist conception [or interpretation] of history,” which he called “a guiding thread for my studies.” Following this historical-materialist thread led Marx to conclude that capitalism is a transitory historical stage that will be superseded and replaced by a less competitive, more cooperative, and truly humane and egalitarian economic and social system.