Augustine covers Heaven and Earth, and has to pull himself back on track sometimes.
To counter people who claim that miracles ceased, he describes some he saw, and others he heard from sources he trusted--and the list is quite long.
He sometimes uses close reading of Scripture, and sometimes explains passages metaphorically. Some of the passages he closely read were ones I considered metaphorical ("Not a hair of your head shall perish"), and he used a version of the Septuagint that seems not quite precise. He knows Jerome's "new" Latin version, and cites it a time or three, but doesn't rely on it much. When his close reading hits a passage that was ill-translated, it's a bit jarring.
He cites books no longer extant--which is frustrating, since I'd really like to have learned more, but most of (e.g.) Varro's work is lost.
The earlier chapters describe details of Roman religion that didn't show up in Bulfinch's Mythology. It's a good reminder of what real pagans are like.
He chews up the pagan philosophers. That isn't hard to do--and they did it to each other with gleeful abandon too.
He has a large chunk of parallel histories of Israel and the rest of the world (Assyria is his generic term for all the empires of that region, fyi), which is interesting, even if his chronology is not 100%. OK, quite a bit less than 100%. Some things he gets wrong--I suppose nobody could read cuneiform by then, and not much hieroglyphic text either, so maybe some of the histories had been lost. I had thought that the claim that all (or almost all) the pagan gods were deified heroes was a late notion, but Augustine cites Roman authors explaining that Mercury and Isis and many others were deified after their deaths. (Isis taught agriculture to the Egyptians?)
He's eager to explain how everything in Israel's history and scripture points to Jesus, and stretches some points way beyond reasonable limits.
When he discusses prodigies, I felt a sharp wish to be able to sit him down and explain a little chemistry and physics. Yes, he mentions the salamander, and a worm that lives in boiling water--and of course the latter does exist though he couldn't know it. And on several other points (predestination) I didn't think he had a solid handle on all aspects of what he was discussing.
Nevertheless, it is interesting.