The first ten of the twenty-two Books (or "chapters") of the City of God contain a declamation against the classical pagans and their gods, and are not included within the synopsis that is provided on this page. The points below are not very encouraging reading for any but the highly virtuous! This is because the message that Augustine gives is, for the most part, a disturbing and sombre one.

It is helpful to be aware that the Roman Catholic Church never formally adopted the opinion of Augustine about the very restricted number who will attain eternal life, nor his reference to a so-called “double predestination” that John Calvin repeated at the time of the Reformation. The Catholic Church has always regarded Augustine as the Professor of Grace (in Latin, gratia), rather than as an example of the Church's position on predestination.          

An overview is presented below:

• Due to the universal contagion of original sin wherein all have sinned in Adam, the human race has deserved to be damned [City of God 21, 12]. We have turned away from God and towards the rule of self [see City of God 13, 14 and 14, 3 & 13].

By means of a grace that we could never merit, from this mass of people God has chosen a small minority who will be saved.

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  The fact that only a small number are saved is itself a means whereby God makes apparent what all in fact deserve [City of God 21, 12].
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  And thus human history is composed of the progress of two cities, the city of God and the city of man [e.g. City of God 14, 28 and 15, 1 & 21].
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  Those who by means of grace (in Latin, gratia) renounce the self and turn towards God, as opposed to the vast majority who have renounced God and turned towards the self [City of God 14, 28].
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  In this life, we can never be sure of which individuals belong to which city [e.g. City of God 20, 27], and thus they are intermingled in a way that thwarts any moral complacency.
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  While the visible church bears a special relation to the city of God, membership in the Church is no guarantee of eternal live [e.g. City of God 20, 9].
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  The history that is visible to us is merely a vestige of the moral drama that takes place beyond the scrutiny of our weak and often proud reasoning [City of God 20, 21 & 22].
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  What is certain is that the linear movement of human history aims at the eventual separation of the two cities [e.g. City of God 20, 21 & 28].
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  Members of each city are to be united with their resurrected bodies [e.g City of God 21, 1 & 3 and 22, 21] and given their respective just rewards:
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  For the small minority saved by the free grace of God, there is the vision of God, a joy we can only dimly discern at the moment [City of God 22, 29].
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  For the overwhelming mass of humanity, there is the second death wherein their resurrected bodies will be subject to lasting pain by flames that will inflict pain without consuming the body [City of God 21, 2-4].
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  The degree of pain will be proportional to the extent of sin [City of God 21, 16], although the duration of the torment is equal in all cases.
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  They must suffer without end, for to suffer any less would be to contradict scripture and undermine our confidence in the eternal life of the small number God has saved [City of God 21, 23].

The material on this page is a precis from http://plato.stanford.edu/entries/augustine/#6 

(Continued on the next page.)

Links

The City of God. This includes a synopsis of every chapter. From the Catholic Encyclopedia. 
http://www.newadvent.org/fathers/1201.htm  

A Reading Plan for Augustine’s City of God. One of the reasons that Augustine’s work remains unread today is because of its length and digressions. In lieu of an abridged version, Michael Haykin of Southern Seminary USA offers a selective reading guide to the book, which I’ve included below for those who want to take up one of the great classics of the Christian tradition.
http://www.thegospelcoalition.org/blogs/justintaylor/2013/11/05/a-reading-plan-for-augustines-the-city-of-god  
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