Books 38-40 of Livy’s History of Rome cover the years 189-179 BC. They contain two famous and much-discussed episodes: the trials of the Scipios, and the so-called Bacchanalian conspiracy. Other notable matters described are the end of the war with the Aetolian League and Manlius Vulso’s campaign in Asia Minor, the censorship of the elder Cato, and the fatal quarrel in the Macedonian royal house. This commentary, conceived on the same scale as Briscoe’s earlier commentaries on Books 31-33 and 34-37, aims to elucidate historical, literary, textual, and linguistic aspects of Livy’s narrative. When Polybius, Livy’s main source for events in the Hellenistic world, full references to the relevant passages of the former are given, with citation of the opening and closing words. A substantial Introduction discusses sources and methods of composition, language and style, the manuscripts, the calendar and chronology, Roman policy in northern Italy, and the Roman legions of the period.