A lost letter to C. Licinius Calvus on the right kind of oratory, referenced at Fam. 15.21.4 and partly preserved through quotation by Quintilian and discussion in Tacitus’s Dialogus de Oratoribus. A central document of the Cicero–Calvus quarrel over Atticist versus Asianist style. The page that follows is an editorial note, not a translation.