The author examines the scope and sources of St Augustine’s knowledge of Manichaeism. He mostly follows the thesis of J.K. Coyle, that as a Christian and anti-Manichaean polemicist, Augustine obtained additional information about the “Religion of Light”. To illustrate Augustine-the-Manichaean and Augustine-the-polemicist’s knowledge of the religion of Mani, the author includes two lengthy excerpts from his writings: from the 7th book of Confessiones and the treatise De natura boni, which features a quotation from the Manichaean work Treasure. The author provides a special comment on this extract.