Cicero in Letters is a guide to the first extensive correspondence that survives from the Greco-Roman world. The more than eight hundred letters of Cicero that are its core provided literary models for subsequent letter writers from Pliny to Petrarch to Samuel Johnson and beyond. The collection also includes some one hundred letters by Ciceros contemporaries. The letters they exchanged provide unique insight into the experience of the Roman political class at the turning point between Republican and imperial rule. The first part of this study analyzes effects of the milieu in which the letters were written. The lack of an organized postal system limited the correspondence that Cicero and his contemporaries could conduct and influenced what they were willing to write about. Their chief motive for exchanging letters was to protect political relationships until they could resume their customary, face-to-face association in Rome. Romans did not normally sign letters, much less write them in their own hand. Their correspondence was handled by agents who drafted, expedited, and interpreted it. Yet every letter advertised the level of intimacy that bound the writer and the addressee. Finally, the published letters were not drawn at random from the archives that Cicero left. An editor selected and arranged them in order to impress on readers a particular view of Cicero as a public personality. The second half of the book explores the significance of leading themes in the letters. It shows how, in a time of deepening crisis, Cicero and his correspondents drew on their knowledge of literature, the habit of consultation, and the rhetoric of government in an effort to improve cooperation and to maintain the political culture which they shared. The result is a revealing look at Ciceros epistolary practices and also the world of elite social intercourse in the late Republic.