Livy's ninth book, one of his finest and most interesting, begins with his celebrated account of the Roman disaster in the Caudine Forks and its aftermath and contains also the famous digression on Alexander and our longest account of the censorship of Appius Claudius Caecus. This new commentary, which is a sequel to those on Books VI-VIII published in 1997 and 1998, deals comprehensively with all aspects of Livy's work, including the literary structure of his narrative, the purpose of the digression on Alexander, the historical and topographical problems of the Samnite Wars, Roman politics in the age of Appius Claudius Caecus, the poetical and archaic language sometimes affected by Livy, and the numerous textual problems posed by the extant manuscripts.