This book provides the Greek text of the Epistula canonica by Gregory of Nyssa. It is a critical edition based on the examination of ca. 150 manuscripts. The preface analyzes the transmission of the text in great detail. Gregory's canonical letter has been part of the canonical letters of the Fathers from the beginning of such collections. The example of a single letter within these collections gives an important insight into the nomocanon-tradition. Gregory's letter is of great interest. It is the only canonical writing presenting a theoretical basis for the canonical penalties...