It is not the consciousness of men that determines their being, but, on the contrary, their social being that determines their consciousness.

Karl Marx

Karl Heinrich Marx (5 May 1818 – 14 March 1883) was a German philosopher, economist, sociologist, historian, journalist, and revolutionary socialist. His ideas played a significant role in the development of social science and the socialist movement. He published various books during his lifetime, with the most notable being The Communist Manifesto (1848) and Capital(1867–1894); some of his works were co-written with his friend and fellow German revolutionary socialist, Friedrich Engels.