Sallust, Gaius Sallustius Crispus (86-35 BCE), a Sabine from Amiternum, acted against Cicero and Milo as tribune in 52, joined Caesar after being expelled from the Senate in 50, was restored to the Senate by Caesar and took part in his African campaign as praetor in 46, and was then appointed governor of New Africa (Numidia). Upon his return to Rome he narrowly escaped conviction for malfeasance in office, retired from public life, and took up historiography. Sallust's two extant monographs take as their theme the moral and political decline of Rome, one on the conspiracy of Catiline and the other on the war with Jugurtha.

Although Sallust is decidedly unsubtle and partisan in analyzing people and events, his works are important and significantly influenced later historians, notably Tacitus. Taking Thucydides as his model but building on Roman stylistic and rhetorical traditions, Sallust achieved a distinctive style, concentrated and arresting; lively characterizations, especially in the speeches; and skill at using particular episodes to illustrate large general themes.

For this edition, Rolfe's text and translation of the Catiline and Jugurthahave been thoroughly revised in line with the most recent scholarship.