Diodoros' Bibliotheke Historike, written in the last half of the first century BC, is a major source for ancient history from earliest times to his own era. This is the first English translation of Books 21-40 (301-62 BC) in seventy years, and the first ever commentary on those portions of the text. Major topics include the history of Sicily, the career of Hannibal, the slave wars that plagued the era, and the increasing instability of the Roman Republic. Diodoros' insight into the events of these years is a major source for that era, but his account, which survives only in fragments excerpted and to some extent paraphrased by later Byzantine scholars, has long been neglected.