There are forty-six authors known to have written about the Hellenistic period: all are lost. For the period after 300 there is no consecutive account of historical events in the eastern Mediterranean basin until researchers come to Polybius' description of the rise of the Achaean League and of the Cleomenean War in Book of his Histories. This chapter examines the lost writers of the period 323 to 217. It considers those historians whose works survive, and examines how these relate to the primary sources. The chapter discusses briefly some of the other sorts of information available to the historian. By far the most important of the lost historians is Hieronymus of Cardia. A source of contemporary material which, like inscriptions is provided by papyri and by ostraca. Coins provide a further useful source of information on the early Hellenistic period. Many inscriptions and coins can only be fully exploited by the historian who studies them in their archaeological context.