John Locke was one of the greatest figures of the Enlightenment, whose assertion that reason is the key to knowledge changed the face of philosophy. These writings on thought, ideas, perception, truth and language are some of the most influential in the history of Western thought.

Throughout history, some books have changed the world. They have transformed the way we see ourselves - and each other. They have inspired debate, dissent, war and revolution. They have enlightened, outraged, provoked and comforted. They have enriched lives - and destroyed them. Now Penguin brings you the works of the great thinkers, pioneers, radicals and visionaries whose ideas shook civilization and helped make us who we are.