Friedrich Engels is important as the junior partner in one of history's most successful intellectual enterprises. Unlike many men in his position, Engels acknowledged his subordination graciously, indeed gloried in it. He was careful never to gainsay the senior partner, Karl Marx (1818–1883), in gross or in detail, even after Marx's death.

A more complete appreciation of Engels's jurisprudence, however, should keep in mind two seeming ironies vis-à-vis Marx. First, Engels, who lacked Marx's formal training in law, nevertheless wrote a good deal more on specifically juridical questions. Engels stated, with characteristic clarity, the materialist conception of law, which Marx gestured at but did not develop: “At a certain, very primitive stage of the development of society, the need arises to bring under a common rule ...