For the most part I will try to avoid some of the more memorable scenes. You probably already know them.
Augustine begins by lamenting his learning of Virgil. Why should he weep over Dido when his teachers did not know enough for him to weep over his own soul? This might seem that Augustine is condemning classical learning, and he probably thought he was, but Augustine’s own life mirrors Aeneas’s, so there is that.
Like Aeneas, Augustine arrives in Carthage. And like Aeneas, Augustine succumbs to its pleasures. He failed to understand that true love was a calm “communion of minds” (2.2). Rather, he sought only to be in love with love.
We also get a profound meditation on the proper ordering of goods. There isn’t just one “flat” good thing in our lives. There is a gradation of goods. We sin by desiring lower goods at the expense of higher. This anticipates his later claim that evil is a lack and/or a perversion of the good.
In books three and four he meets a number of important people. He meets Cicero in a book, and Cicero teaches him to seek after higher things. Unfortunately, he also becomes a Manichee. From the Manichees he learned wrong ideas of God and evil. He thought substances must be physical, and so he could not imagine an immaterial substance (3.7).
He also met Faustus, the leader of the Manichees. Ironically, this would lead him out of Manicheanism. He was underwhelmed. Most importantly, he meets Ambrose in Italy, and in Ambrose’s rhetoric he sees that form = substance.
Although in book seven he was still struggling with Manicheanism, he found the Platonists’ books. This reoriented him to the possibility of immaterial substances. He now saw reality as a chain of being. Things are good, and the lower a good is, the more susceptible to corruption it is. This was a breakthrough. Evil couldn’t exist unless there was already a good for it to corrupt. Evil, therefore, is a lack.
Book 8 contains his famous conversion scene. It is dramatic psychology. You’ll have to read it. It also takes place in a garden. That is typology and very important.
Book 9 contains the baptisms of him, his son, Nebredius (I think), and Alypius.
Books 10-13 are extended meditations on memory, time, and creation.
In terms of reading and appreciating the Great Christian Tradition, this is the classic text with which to start.