Cyril ibn Laqlaq’s Book of Confession offers the critical edition and translation of a treatise that is published here for the first time. Cyril, the 75th Coptic Patriarch, was a controversial figure who was judged for simony by his own bishops in an official synod. Despite his failure to promote auricular confession during his lifetime, the widespread distribution of his treatise had a significant impact on the practice's adoption. The Book of Confession is well attested in the manuscript tradition. The vast inventory of manuscripts attests to its popularity among diverse Christian denominations throughout the Middle East. Undoubtedly, it has been a highly influential text in the formation of spiritual life and penitential theology in the Middle Ages.