This is a review of "De Oratore" books I-II and "De Oratore" book III in the Loeb Classical Library.
Marcus Tullius Cicero may not have been the greatest trial lawyer of ancient Rome, but he is the best remembered. He wrote much on many subjects, and some of his private correspondence also survives. He did his best writing in the field of rhetoric. Although he was not an original thinker on the subject of rhetoric, "De Oratore" shows him to have had an encyclopedic practical knowledge of oratory in general and criminal trial advocacy in particular.
Cicero wrote "De Oratore" as a dialog among some of the preeminent orators of the era immediately preceding Cicero's time. The occasion is a holiday at a country villa, and the characters discuss all facets of oratory, ceremonial, judicial, and deliberative. They devote most of the discussion to judicial oratory, and their discussion reveals the trial of a Roman lawsuit to be somewhat analogous to the trial of a modern lawsuit. You have to piece it together from stray references to procedure scattered throughout the work, but it appears that a Roman trial consisted of opening statements, the taking of evidence, and final arguments. Modern trial advocacy manuals devote most of their attention to the taking of evidence, but Cicero dismisses the mechanics of presenting evidence as relatively unimportant compared to the mechanics of presenting argument.
"De Oratore" is divided into three books. The first speaks of the qualities of the orator; the second of judicial oratory, and the third of ceremonial and deliberative oratory. The modern trial lawyer would find the second book most interesting and most enlightening. A lot about trial advocacy has changed since Cicero's day (e.g. no more testimony taken under torture), but a lot hasn't.. Much of what Cicero says holds true even in the modern courtroom.
Trial lawyers cannot congregate without swapping "war stories," and Cicero's characters are no exception. They pepper their discussion with references to courtroom incidents which have such verisimilitude that they could have happened last week instead of 2,000 years ago. I have no doubt that Cicero, had he lived today, would have made a formidable trial lawyer.
The Loeb Classical Library edition of "De Oratore" consists of two volumes. Volume one contains Books I and II of "De Oratore," and volume two contains Book III along with two shorter philosphical works and "De Partitione Oratoria." "De Partitione" purports to be a discussion between Cicero and his son on oratory. "De Partitione" differs so much from "De Oratore," that many (myself included) doubt Cicero wrote it.