Final answer:
Karl Marx co-authored 'The Communist Manifesto' with Friedrich Engels in 1848, outlining their ideas on society and capitalism.
Step-by-step explanation:
Karl Marx, a German philosopher and economist, co-authored The Communist Manifesto with Friedrich Engels in 1848. This political manuscript is one of the most influential in history and presents Marx's theory of society.
Marx and Engels collaborated on this work, which outlined their ideas on class struggle and the eventual overthrow of capitalism.