He was relatively unknown in his lifetime, but Karl Marx's theories about society, economics, and politics changed the world, led to the Russian Revolution and the formation of the Soviet Union and the creation of the People's Republic of China, and inspired variants from Leninism and Stalinism to Trotskyism and Maoism. Marx is one of the most influential thinkers of the modern age, but in recent times "Marxism" has become a vague, contestable, and uncertain term. In this concise, accessible book, Paul Thomas casts a clarifying light on Marx's life and writings, providing a coge