Book 1 of De Natura Deorum exhibits in a nutshell Cicero's philosophical method, with the prior part stating the case for Epicurean theology, the latter (rather longer) part refuting it. Thus the reader observes Cicero at work in both constructive and skeptical modes as well as his art of characterizing speakers. Prefaced to the Book is Cicero's most elaborate justification of his philosophical writing. The Book thus makes an ideal starting point for the study of Cicero's philosophica or indeed of any philosophical writing in Latin, since it delineates the problems such a project raised in the minds of Roman readers and shows how Cicero thought they could be met. There is also a systematic and detailed doxography of ancient views about the deity, an important document in itself, presented from an Epicurean perspective. The volume's Introduction situates this text within Cicero's intellectual development and ancient reflection about the gods.