Karl Marx, an tireless theorist, did not establish a doctrine but rather read, excerpted, commented, drafted, rejected, and continually started anew. Only a fraction of his thoughts was published by him, and to this day not everything has been edited. This introduction by Christian Schmidt illustrates what the tireless research drive of the philosopher and economist responded to, namely the question: What actually hinders the implementation of Hegel's program for the realization of freedom and reason? Marx meticulously sought in modern society the partly unconscious forces and mechanisms that transform freedom and equality into oppression and exploitation. The volume explains the essential steps towards a demanding and complex critique of capitalist reality.