The Confessions of St. Augustine

Confessions is generally considered one of Augustine's most important texts. It is widely seen as the first Western autobiography ever written (Ovid had invented the genre at the start of the first century AD with his Tristia) and was an influential model for Christian writers throughout the Middle Ages. Henry Chadwick wrote that Confessions will "always rank among the great masterpieces of Western literature."
The work is not a complete autobiography, as it was written during Augustine's early 40s, and he lived long afterward, producing another important work, The City of God. Nonetheless, it does provide an unbroken record of his development of thought and is the most complete record of any single person from the 4th and 5th centuries. It is a significant theological work, featuring spiritual meditations and insights.