Karl Marx was born in the German city of Trier in 1818. He studied law in Bonn and Berlin at his father's insistence, but his true interests lay elsewhere and, in 1841, he received a doctorate in philosophy from the University of Jena.

For the next two years he wrote for radical left-wing newspapers before moving to Paris with his wife, Jenny; there he became a communist and met his lifelong friend and collaborator, Friedrich Engels.

They published their revolutionary pamphlet, The Communist Manifesto, in 1848 and Marx moved to London a year later. He spent the rest of his life there - often in considerable poverty - while he wrote his magnum opus of political theory, Das Kapital. Karl Marx died in 1883.

Franz Kafka (1883 - 1924) is a Jewish Czech who wrote in German, and who ranks among the twentieth-century's most acclaimed writers. His works evoke the bewildering oppressiveness of modern life, of anxiety and alienation in a world that is largely unfeeling and unfamiliar.

Although most of his work was published posthumously, his body of work, including the novels 'The Trial' (1925) and 'The Castle' (1926) and the short stories including 'The Metamorphosis' (1915) and 'In the Penal Colony' (1914), is now considered among the most original in Western literature.

Henry David Thoreau (1817-62) was born in Concord, Massachusetts and educated at Harvard. He became a follower and a friend of Emerson, and described himself as a mystic and a transcendentalist.

Although he published only two books in his lifetime, Walden is a literary masterpeice and one of the most significant books of the nineteenth century.