JAMES CROSSLEY'S BOOK is reviewed in The Chronicle of Higher Education. It requires a paid subscription to access it, but here's the abstract:

Why Early Christians Stopped Observing Jewish Codes

By DAVID GLENN

James G. Crossley, a lecturer in New Testament studies at the University of Sheffield, in England

Jesus of Nazareth obeyed kosher dietary rules and otherwise followed traditional Jewish codes of conduct — but within 20 years after his death, the Christian movement had jettisoned many of those laws. In Why Christianity Happened: A Sociohistorical Account of Christian Origins (26-50 CE) (Westminster John Knox Press), Mr. Crossley argues that that broad shift away from law observance was both a cause and an effect of the religion's rapid spread among Gentiles.