The Confessions is a very dense and spiritual book which chronicles the life of Saint Augustine of Hippo, an exploration and study of memory and his analysis and interpretation of the book of genesis. Books one through nine chronicles his life, in which he describes episodes of his life where he can find parallels to the Old Testament and other parts of his life that exhibit god's grace. Book ten is a contemplation of memory and an analysis of himself, where he observes the wonders of the external world and relates it to an introspective study of himself. The last two books are a study of scripture where he concentrates heavily on Genesis and the methods of god's creation of the earth.
While many people throughout history have written many autobiographies and biographies St. Augustine of Hippo is very selective about which narratives he includes in his book The Confessions. Saint Augustine says "I pass over many things, hastening on to those which more strongly compel me to confess to thee,", so we know he passed over a large amount of his life not exactly giving us an exactly holistic picture. He brings up instances in his life like the time when he stole pears from a pear tree and fed them to swine comparing it with Adam and Eve stealing Apples in the Garden of Eden.
Many have said that The Confessions are very much like a parallel of the Parabal of the Prodigal Son which appears in Canonical gospels of the New Testament specifically Gospel of Luke (Luke 15:11-32). It resembles this story because Augustine's heart is "restless till it finds its rest in God"; he brings his story to an end, after his struggles to free himself from pride, sensuality and other sins, with his return to his home at Tagaste.
Augustine's tone in this book is very inspirational and at the same time very agnostic which is probably what made him very controversial during his time.