This critical study analyzes direct evidence concerning the life and lost works of Theopompus of Chios, the 4th-century BC historian and orator. In a translation of surviving citations of Theopompus' work and of the references made to Theopompus' work by other writers, the text makes available all that remains of Theopompus' writings. Theopompus was primarily known in antiquity for his historical works, which included "Hellenica", a 12-volume history of Greece, and the 58-volume "Philippica", which focused mainly on the career of Philip II of Macedon. All of Theopompus' works were lost by late antiquity except 53 volumes of the "Philippica", which survived into Byzantine times only to disappear by the 10th century. Concentrating on the "Hellenica" and the "Philippica", the author of this text studies the fragments to reveal what can be gleaned about the scope and content of Theopompus' two major works. He deals systematically with the problems of interpretation and makes clear the methodological background of his reconstructions and evaluations, furnishing the basis for further methodological debate. Theopompus' moral and political views are discussed, as are his treatment of two of the most important figures of the middle of the 4th century BC, Philip and Demosthenes. In addition, there is an index of the proper names found in the fragments.