The writings of the ancient Roman philosopher Seneca offer powerful insights into stoicism, morality and the importance of reason, and continue to provide profound guidance to many through their eloquence, lucidity and wisdom.

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. The Penguin Great Ideas series brings you the works of the great thinkers, pioneers, radicals and visionaries whose ideas shook civilization, and helped make us who we are.