The Roman Stoic philosopher Lucius Annaeus Seneca is one of the most widely read authors in modern times. The moral philosophy of Stoicism again and again turns out to be alive and in demand in conditions of religious decline, moral degradation and social unrest. This is a teaching about how to live with dignity and meaning for a person who has nothing to believe in and no one to hope for, a kind of spiritual therapy, a preaching of perseverance in the face of loss, pain or even death - one’s own, the state’s, the entire universe. Ethics for Seneca is the center and goal of philosophy; the doctrines of nature, knowledge and divinity are subordinate to it. Seneca’s ethical treatises are intended for a wide range of readers. The treatise “On Nature” is one of the most important sources for historians and philosophers. Most of the treatises collected in this volume are published for the first time.