In doing so, Hunt challenges several persistent popular assumptions. Engels was not the hired help who provided empirical backfill for Marx's theoretical canvasses. He was a highly original theorist in his own right, who made a number of foundational contributions - notably, the application of the Feuerbachian concept of "alienation" to the sphere of political economy - to what would later be understood as "Marxist orthodoxy". It is not true, more-over, that Engels distorted or rigidified the philosophical substance of Marx's thought through an over-emphasis on the primacy of the dialectic (a claim to this effect has often been reiterated). As Hunt shows, Engels's deepening interest in the dialectical method from around 1870 was fully endorsed and authorised by Marx. Marx and Engels diverged, moreover, over important issues such as Russian populism, which Marx found attractive for a time, but Engels strenuously rejected.

Above all, Hunt captures with a combination of sweeping panoramas and brilliantly painted miniatures the world in which Engels's mind and thinking developed. Evangelical Protestantism, German Romanticism, Straussian Bible criticism, Hegelianism, Feuerbach and the inchoate cultural radicalism of Young Germany - Hunt shows how the young Engels acquired a sense of who he was through his passionate engagement with a succession of cultural moments: "I cannot sleep at night, because of all the ideas of the century," he wrote in 1839.

It was a very English life. Engels arrived in Manchester in 1842, when he was only 22, and spent most of the rest of his life in England. The Marx-Engels letters, though primarily in German, were peppered with English phrases, including recherché colloquialisms. Hunt deftly sketches in the Manchester and London worlds in which Engels moved, doing justice to the diversity of Victorian social-critical discourses and their influence on the young revolutionary ideologue. Engels's debt to Thomas Carlyle in particular is cast into fascinating relief. As Hunt shows, there are metaphors in The Condition of the English Working Class, Engels's trenchant, Manchester-based study of proletarian misery, that stem directly from Carlyle's Signs of the Times.