This lucid and wide-ranging book (developed from a doctoral dissertation) assembles a dossier of official letters which were prompted by the acquittal of Pelagius at the Synod of Diospolis (415). Augustine's letter-collection supplies three letters from the bishops of Africa to Innocent of Rome (epp. clxxv–clxxvii, written, Dalmon thinks, by Augustine), with Innocent's replies (epp. clxxxi–clxxxiii); two letters from Augustine to the future Sixtus iii of Rome (epp. cxci, cxciv); and an imperial rescript of 419 (ep. cci). The Collectio Avellana provides three letters from Zosimus of Rome to the African Churches. Dalmon's extensive introduction (pp. 7–256) offers five chapters covering (1) the Pelagian question before 416, including texts, people, social and theological context and events; (2) the theological and political moves of Pelagians who appealed from one synod to another, and of their opponents, especially in Africa, who wanted support from Rome without conceding papal primacy; (3) ‘chancery style’ including prose rhythm, the forms of official records and correspondence, and the roles of administrative staff and letter-bearers; (4) the construction of heresy in Africa and at Rome, with detailed attention to themes and vocabulary; and (5) the complex history of textual transmission and the making of collections. Dalmon then prints the Latin texts, with critical apparatus, a new translation, detailed annotation on style and content, and longer ‘notes complémentaires’ in the great tradition of the Bibliothėque Augustinienne. She provides her own text of the letters of Zosimus, but otherwise follows Goldbacher's CSEL edition, which she has re-examined. Dolman also offers an extensive bibliography, and tables of parallel passages and Scripture references in the works of Augustine. This is a valuable and informative study of history, theology, literary and linguistic questions, and the practicalities of discussion by letter.