An epic poem written in Latin as De rerum natura by Lucretius which explores the materialist philosophy of the Greek philosopher Epicurus. Lucretius divided his argument into six books. Books I and II establish the main principles of the atomic universe. Book III demonstrates the atomic structure and mortality of the soul and ends with a triumphant sermon on the theme "Death is nothing to us." Book IV describes the mechanics of sense perception, thought, and certain bodily functions and condemns sexual passion. Book V describes the creation and working of the world and the celestial bodies and the evolution of life and human society. Book VI explains remarkable phenomena of the earth and sky, in particular, thunder and lightning. Using poetic language and metaphor, the Lucretius describes a world ruled by physical principles, rather than the divine will. Called the "the most complete analysis of the atomic composition of matter prior to twentieth-century nuclear physics."