Stephen Kotkin is the John P. Birkelund Professor in History and International Affairs at Princeton University. He is also a fellow at the Hoover Institution at Stanford University.

He directs Princeton's Institute for International and Regional Studies and co-directs its Program in the History and Practice of Diplomacy.

His books include Uncivil Society, Armageddon Averted, and Magnetic Mountain. Kotkin was a Pultizer Prize finalist for Stalin: Volume I: Paradoxes of Power, 1878-1928.

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.