The monograph is an experience of studying one of the most important components of the historical reality of the human moral world. The study is devoted to the confessional texts of the Russian Middle Ages, guided by which the penitent revealed his sins to the confessor, both ordinary and the most hidden. The study of confessional questionnaires allows you to penetrate the privacy and inner world of a person and trace the formation and change of ideas about sin and virtue. The book attracts a wide range of penitential texts of the XIV-XIX centuries, extracted from Russian, South Slavic and Ukrainian manuscript books, a significant part of this material is introduced into scientific circulation and published for the first time.