Saint Ambrose of Milan is one of the towering figures of the late 4th century AD. A high official in the western Roman government, Ambrose was conscripted against his will by the people of Milan to serve as their bishop. He would go on to become one of the most important fathers of the Western Church: a fierce opponent of heretics, admonisher of emperors, voluminous writer, worker of miracles, and the spiritual father of other great saints.

This 5th century AD biography of Ambrose was written by one of the deacons who served under him: Paulinus of Milan. Paulinus was encouraged in this biographical effort by none other than Saint Augustine of Hippo, Ambrose's most famous disciple. Written in a style similar to other works of hagiography from the same time, Paulinus places Ambrose in his historical and spiritual context, drawing an enduring picture of the man and his times that has helped to cement Ambrose as one of the great holy men of the ancient Church.

As a primary source, The Life of Saint Ambrose includes numerous first-hand accounts which were witnessed by Paulinus himself or related to him by those close to Ambrose. The important figures whose lives intersected with that of Ambrose included the Roman emperors Gratian, Theodosius the Great, and Valentinian II; the Arian empress Justina; usurpers Eugenius and Arbogast; the magister militum Stilicho, and saints like Marcellina, Simplicianus, Bassianus, Venerius, and many others.

This version of the Vita Sancti Ambrosii was rendered into English by Sr. Mary Kaniecka in 1928. It has been completely re-typeset for the modern reader with simplified punctuation, expanded bibliography, updated citations, and an index. It retains Sr. Kaniecka's introduction and historical commentary, and includes numerous additional notes added by the modern editor. (Note: this edition does not include Sr. Kaniecka's revised Latin text nor her commentary specific to the translation.)