The Brutus or De claris oratibus is a dialogue by Cicero, surviving in somewhat fragmentary condition, on the history of oratory in Greece and Rome. The setting is a conversation between Cicero, his friend Atticus, and Marcus Junius Brutus, the later assassin of Caesar. Cicero comments on Greek oratory which he divides into Attic, Asianic and Rhodian schools, before considering Roman statesmen from the legendary Brutus the Liberator onwards.
Free online texts
Attalus: Brutus, a History of Famous Orators, translated by E. Jones (1776). HTML format.
Gutenberg: Cicero's Brutus or History of Famous Orators; also His Orator, or Accomplished Speaker, translated by E. Jones. Multiple formats.
Latin Library: Brutus. Latin text, HTML format.
Perseus: Brutus. Latin text, HTML and XML formats.
Wikisource: Brutus. Latin text, multiple formats.
History of Philosophy without any gaps: Rhetorical Questions: Cicero - podcast by philosopher Peter Adamson.
History of Philosophy without any gaps: Raphael Woolf on Cicero - podcast by philosopher Peter Adamson.
Internet Encyclopedia of Philosophy: Cicero.
The Great Conversation: Further reading at Tom's Learning Notes
Cicero: On the Orator.
Cicero: Letters to Atticus.
Tacitus: Dialogue on Orators.
Latin resources: Learn to read Latin texts in the original.