In the year 62, citing health issues, the Roman philosopher Seneca withdrew from public service and devoted his time to writing. His letters from this period offer a window into his experience as a landowner, a traveler through Roman Italy, and a man coping with the onset of old age. They describe the roar of the arena, the festival of Saturnalia, and the perils of the Adriatic Sea, and they explain his thoughts about political power, the treatment of slaves, the origins of civilization, and the key points of Stoic philosophy. This selection of fifty of his letters brings Seneca to readers in a fresh modern voice and shows how, as a philosopher, he speaks to our time. Above all, these letters explore the inner life of the individual: from the life of heedless vanity to the first interest in philosophy, to true friendship, self-determination, and personal excellence.