Frederick Engels is widely remembered as the sidekick of Karl Marx, but he was an important figure in his own right. As a fox hunting factory owner he was in some ways an archetypal upper class Victorian gentleman, and even his interest in social reform and the welfare of the lower orders was not unique. The nineteenth century was an age of political dynamism and change, and optimism about the future. It has even been argued that Marxism is a quintessentially nineteenth century ideology, with its sense of thrusting political agency and faith in the idea of human progress. A century and a half on, however, the lives and work of Marx and Engels remain of interest not only to those who are nostalgic for Communism, but to anyone interested in political ideas.

Is this interest merely historical, or are there lessons for our own very different times? In particular, what difference do individual thinkers and campaigners make? Are they merely vehicles for anonymous historical forces, as some Marxists have argued? Could Marx have written ‘Capital’ without the financial and intellectual support of Engels? Does it matter? How should we understand the interplay of individual lives, political ideas and the material world today?