After Marx’s death (1883), Engels served as the foremost authority on Marx and Marxism. Aside from occasional writings on a variety of subjects and introductions to new editions of Marx’s works, Engels completed volumes 2 and 3 of Das Kapital (1885 and 1894) on the basis of Marx’s uncompleted manuscripts and rough notes. Engels’s other two late publications were the books Der Ursprung der Familie, des Privateigenthums und des Staats (1884; The Origin of the Family, Private Property and the State) and Ludwig Feuerbach und der Ausgang der klassischen deutschen Philosophie (1888; Ludwig Feuerbach and the Outcome of Classical German Philosophy). All the while he corresponded extensively with German social democrats and followers everywhere, so as to perpetuate the image of Marx and to foster some degree of conformity among the “faithful.” His work was interrupted when he was stricken with cancer; he died of the disease not long after.

During his lifetime, Engels experienced, in a milder form, the same attacks and veneration that fell upon Marx. An urbane individual with the demeanour of an English gentleman, Engels customarily was a gay and witty associate with a great zest for living. He had a code of honour that responded quickly to an insult, even to the point of violence. As the hatchetman of the “partnership,” he could be most offensive and ruthless, so much so that in 1848 various friends attempted unsuccessfully to persuade Marx to disavow him.

Except in the Soviet Union and other communist countries, where Engels received due recognition, posterity has generally lumped him together with Marx without adequately clarifying Engels’s significant role. The attention Engels does receive is likely to be in the form of a close scrutiny of his works to discover what differences existed between him and Marx. As a result, some scholars have concluded that Engels’s writings and influence are responsible for certain deviations from, or distortions of, “true Marxism” as they see it. Yet scholars in general acknowledge that Marx himself apparently was unaware of any essential divergence of ideas and opinions. The Marx-Engels correspondence, which reveals a close cooperation in formulating Marxist policies, bears out that view.

Biographical and critical studies include Tristram Hunt, Marx’s General: The Revolutionary Life of Friedrich Engels (2009); John Green, Engels: A Revolutionary Life: A Biography of Friedrich Engels (2008); J.D. Hunley, The Life and Thought of Friedrich Engels: A Reinterpretation (1991); Terrell Carver, Engels (1981, reissued 1991), on the development of Engels’s materialist interpretation of history, Marx & Engels: The Intellectual Relationship (1983), on Engels’s revisionism, and Friedrich Engels: His Life and Thought (1989); W.O. Henderson, The Life of Friedrich Engels, 2 vol. (1976); and Gustav Mayer, Friedrich Engels: A Biography (1936, reissued 1969).