Rousseau's explosive cry for human liberty helped to spark the French Revolution and has haunted our discussions of how we should rule one another ever since - seen as both a blue-print for political terror and as a fundamental statement of democracy.

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.