The purpose of this article is to clarify some basic features of historical materialism insofar as it is a philosophic conception of history. Every serious philosophy of history must give an answer to at least three questions: What is the nature of historical reality? How is historical change being accomplished? What are the possibilities, the scope and the limits of historical knowledge?In historical materialism not one of these questions is sufficiently resolved. Contrary to Marxist-Leninist assertions, there is no "necessary" and "inseparable" connection between dialectical and historical materialism. A materialist conception of history is compatible with many non-materialist metaphysical views. Further, historical materialism uses a superseded monocausal model of historical flux. Moreover, it is based upon a notion of historical causality which simply reproduces mechanical causality; but mechanical causality is inapplicable to historical events. Finally, the critique of historical knowledge isterra incognita for historical materialism.