If you can find a copy of the Oxford Classical Dictionary 3rd edition at your library or a University Library, I recommend you look at the articles there on "Jews" and "Christianity."
Additionally, some other books addressing the social context of early Christianity would be:
W.H.C. Frend, The Rise of Christianity
J. Gager, Kingdom and Community: The Social World of Early Christianity
W. Meeks, The First Urban Christians: The Social World of the Apostle Paul
R. Markus, Christianity in the Roman world
and has R Lane Fox, Pagans and Christians already been mentioned?
There are many good works out there produced by classical scholarship. Good luck!
Euripides