Friedrich Engels (28 November 1820 – 5 August 1895) was a German social scientist, author, political theorist, philosopher, and father of Marxist theory, alongside Karl Marx. In 1845 he published The Condition of the Working Class in England, based on personal observations and research. In 1848 he co-authored The Communist Manifesto with Karl Marx, and later he supported Marx financially to do research and write Das Kapital. After Marx's death, Engels edited the second and third volumes. Additionally, Engels organized Marx's notes on the "Theories of Surplus Value" and this was later published as the "fourth volume" of Capital. He has also made important contributions to family economics.
Vladimir Lenin wrote: "After his friend Karl Marx (who died in 1883), Engels was the finest scholar and teacher of the modern proletariat in the whole civilised world.... In their scientific works, Marx and Engels were the first to explain that socialism is not the invention of dreamers, but the final aim and necessary result of the development of the productive forces in modern society. All recorded history hitherto has been a history of class struggle, of the succession of the rule and victory of certain social classes over others
Engels is commonly known as a "ruthless party tactician", "brutal ideologue", and "master tactician" when it came to purging rivals in political organizations. However, another strand of Engels's personality was one of a "gregarious", "bighearted", and "jovial man of outsize appetites", who was referred to by his son-in-law as "the great beheader of champagne bottles." His interests included poetry, fox hunting, and hosting regular Sunday parties for London's left-wing intelligentsia where, as one regular put it, "no one left before two or three in the morning." His stated personal motto was "take it easy", while "jollity" was listed as his favorite virtue.