In summery, Augustine was pretty lost. He was corrupt as a kid, committed a decent amount of intercourse out of wedlock, and although his mother pored her soul out in prayers for his faith he still did not believe until God directly influenced him.
It's a great book and worth the read, especially if you are currently struggling/stagnant in the faith. The way it is written is to be an autobiographical prayer to God where Augustine reveals all of the work that God has done to/through him in order to save his soul.
Here are some great quotes from the book:
"Those who look for the Lord will cry out in praise of him, because all who look for him shall find him, and when they find him they will praise him." p 1.
"Even as a child I existed, I was alive, I had the power of feeling; I had an instinct to keep myself safe and sound, to preserve my own being, which was a trace of the single unseen Being from whom it was derived; I had an inner sense which watched over my bodily senses and kept them in full vigour; and even in the small things which occupied my thoughts I found pleasure in the truth. I disliked finding myself in the wrong; my memory was good; I was acquiring the command of words; I enjoyed the company of friends; and I shrank from pain, ignorance, and sorrow. Should I not be grateful that so small a creature possessed such wonderful qualities? But they were all gifts from God, for I did not give them to myself." p 11.
"In your eyes my beauty vanished and I was foul to the core, yet I was pleased with my own condition and anxious to be pleasing in the eyes of men." p 12.
"My real need was for you, my God, who are the food of the soul, I was not aware of this hunger. I felt no need for the food that does not perish, not because I had had my fill of it, but because the more I was starved of it the less palatable it seemed." p 17.
"Men are so blind that they even take pride in their blindness." p 18.
"Wherever we taste the truth, God is there. He is in our very inmost hearts, but our hearts have strayed from him. Think well on it, unbelieving hearts and cling to him who made you. Stand with him and you shall not fall; rest in him and peace shall be yours." p 27.
"How can life be happy where there is no life at all? | Our Life himself came down into this world and took away our death." p 27.
"In my pride I was running adrift, at the mercy of every wind. You were guiding me as a helmsman steers a ship, but the course you steered was beyond my understanding." p 30.
"The soul is weak and helpless unless it clings to the firm rock of truth." p 31.
"The light is clouded over and the truth cannot be seen, although it is there before our eyes." p 31.
"I had my back to the light and my face was turned towards the things which it illumined, so that my eyes, by which I saw the things which stood in the light, were themselves in darkness." p 33.
"When you are our strength we are strong, but when our strength is our own we are weak." p 34-35.
"Accept my confessions, O Lord. They are a sacrifice offered by my tongue, for yours was the hand that fashioned it and yours the spirit that moved it to acknowledge you." p 36.
"Man's heart may be hard, but it cannot resist the touch of your hand." p 36.
"What else can save us but your hand, remaking what you have made?" p 41.
"I believed countless things which I had never seen or which had taken place when I was not there to see - so many events in the history of the world, so many facts about places and towns which I had never seen, and so much that I believed on the word of friends or doctors or various other people. Unless we took these things on trust, we should accomplish absolutely nothing in this life." p 50.
"We are too weak to discover the truth by reason alone." p 51.
"You are there to free us from the misery of error which leads us astray, to set us on your own path and to comfort us by saying, 'Run on, for I shall hold you up. I shall lead you and carry you on to the end.'" p 54.
"I should only be shielding my eyes from seeing you, not hiding myself from you." p 84.
"So, O Lord, all that I am is laid bare before you. I have declared how it profits me to confess to you. And I make my confession, not in words and sounds made by the tongue alone, but with the voice of my soul and in my thoughts which cry aloud to you. Your ear can hear them." p 84.
"I call you to come into my soul, for by inspiring it to long for you you prepare it to receive you. Now, as I call upon you, do not desert me, for you came to my aid even before I called upon you. In all sorts of ways, over and over again, when I was far from you, you coaxed me to listen to your voice, to turn my back on you no more, and to call upon you for aid when, all the time, you were calling to me yourself." p 108.
"We had deserted you. But you, who are the one God, the good God, have never ceased to do good." p 114.
"We must ask it to you, seek it in you; we must knock at your door. Only then shall we receive what we ask and find what we seek; only then will the door be opened to us." p 114.
Check out his secure defense of the faith.