Book XII argues that evil is non-existent, being the turning away of a creature from God to itself, and Book XIV distinguishes two cities, one characterized by love for the creator and the of by love for the created.  
Book XV discusses early man, Adam, Cain, and the patriarchs, and the nature of the giants in the earth at that time.  The first seven books talk about the futility and obscenity associated with the worship of pagan gods, decry astrology, and praise Varro for his views on these subjects.  The intention is to prove that Christian worship is not to blame for contemporary difficulties.  Book XII argues that evil is non-existent, being the turning away of a creature from God to itself, and Book XIV distinguishes two cities, one characterized by love for the creator and the of by love for the created.  FTP name this work completed in 426 by Augustine.
Book XV discusses early man, Adam, Cain, and the patriarchs, and the nature of the giants in the earth at that time.  
The City of God