Yes, I know it's a kid's book, but I really love almost anything Rick Riordan writes. The Percy Jackson and the Olympians series is a favorite of mine. It's all about the Greek Pantheon and their children, the demigods. In this spin off series, he tackles the Roman pantheon!
I can't tell you how thrilled I was to see a good description of Rome proper, the buildings, the clothing and armor, the major and minor deities, the temples, auguries.... and even the Lares! Yes, there was a comical treatment (Mr. Riordan seems to like making ghostly characters the butt of jokes), but I was delighted to just see them addressed as part of the every day life of the citizens.
One of the things I enjoyed most about the book was how they drew the distinctions between the Greek and Roman deities such as Greek Hades and Roman Pluto, and Greek Ares and Roman Mars. He illustrated the differences very well, including how Pluto was also a deity of wealth, not just death.
I was disappointed in the simplified "Romans imported the Greek Gods and perfected them" explanation. In The Lost Hero, the first book of this spin off series, Heroes of Olympus, there was the promise of a much deeper, much more clever connection between the two pantheons, much the same way Riordan explained the vast differences in Egyptian lore in his Kane Chronicles books.
We also get to experience some of the military jargon of the Roman army, including one of my favorite words: Cohort. I love talking about my cohorts! Where'd the word come from? Italy! Ha! It's a military unit, 1/10 of a Legion.
The last nifty detail I will mention is that each of the Roman demigods gets a magical tattoo when they become an official member of the legion:
Senatus Populusque Romanus.
The Senate and People of Rome.