Author: Augustine of Hippo
Publication: A.D. 426, De Civitate Dei Contra Paganos, trans. Marcus Dods 1880ish
Length: XXII Books, or 867 pages in my edition
Target Audience: Educated 5th Century Christians
So, my thanks to my college for finally forcing me to read this. I started it in years prior something around three times and always bogged down about Book IV. That said, I recommend you take more than the three weeks I had to read this if you want to do anything else with your brain. It was... rough. However, the sensation of finishing it at 0030 in the morning of September the tenth is one I will long relish.
Augustine contrasts the City of God with the City of Man, the citizens of this world with those of the next. Lots of excellent stuff, some interesting stuff, and some stuff that makes you wonder why that was important fifteen hundred years ago. Now, if you're only going to read one thing by Augustine, read Confessions, but this is great as well. Just take the good bishop up on his apology to those who think he wrote too much at the end!
Recommended (for the stout of heart).