The author was, when he wrote this, a professor of the history of Christianity at Notre Dame. It’s worth reading, and has some good insights, but I found it only good, not great.
The basic organization of the book is to show the way a series of important, representative Romans looked at Christians (and Christianity) and how the perception evolved over the first two centuries: Pliny the Younger, Galen, Celsus, Porphyry, and (the Emperor) Julian. Some insights:
- Christian groups were similar in some respects to civic/trade burial societies.
- Roman religion was secular/civil/traditional (chapter 3).
- Jews were a surprisingly large minority group in the empire (4-6 million out of 60 million) and fairly influential civically (113-14).
- The fact that Jews rejected the Christians was a significant problem for the Romans.
- Some Romans believed in a sort of uber-god who ruled over the lesser gods (like Zeus et al.).
I don’t always agree with the author’s reasoning or Biblical views, but he’s presumably Christian, and the book has a strong ending, about how the critique of the pagans made Christianity stronger.