This work contains Marx’s formulation of the so-called materialist conception of history: “In the social production of their life, men enter into definite relations that are indispensable and independent of their will, relations of production which correspond to a definite stage of development of their material productive forces.” Marx also believed that there are no “ideals” that cannot be realized, for the emergence of new aims is itself an index to the presence of forces which make for their realization. “Therefore mankind always sets itself only such tasks as it can solve; since, looking at the matter more closely, it will always be found that the task itself arises only when the material conditions for the solution already exist, or are at least in the process of formation.” [1961]