No, not really. There was some discussion of what the Christian population in the Arabian peninsula in the 6th and 7th centuries AD believed, and how they influenced Mohammad, but their beliefs were pretty far from the standard Christian beliefs today, or what was at the time starting to be standardized in Byzantine (i.e., they didn't believe in the concept of the Trinity). That's very much a minor footnote in the book as a whole. I wouldn't pick up this book if you're looking for a history of the Christian church.