From his first publication, Aratos of Sicyon (1933), to his death in 2008, F. W. Walbank established himself as one of the leading ancient historians of the last century. His many publications - not least his three-volume commentary on the Greek historian of Roman power, Polybius - transformed the study both of Polybius and of the history of the Hellenistic world. Polybius and his World honours Walbank's achievement by bringing together a number of leading scholars in the fields of Hellenistic historiography and history. The twenty chapters, including an introduction by the volume's editors, re-examine a number of central Polybian themes: Polybius' position between Greece and Rome, his account of the Roman constitution, and the relationship of his work with Xenophon, Phylarchus, Aratus of Sicyon, and Livy (amongst others). The book looks at Polybius' text in the light of narratological perspectives and for the wealth of source material it offers for the economic historian, whilst three chapters also consider aspects of Walbank's own life and work, especially the relationship between his political commitments and his academic work, the genesis of his Polybian commentary, and the personal backdrop to his career.