[Fluribus]

Rodney Stark, after many years of service to the kingdom of Id, became a sociologist and wrote a bunch of books. Three of those books are available at Amazon for the brave price of $1.99.

The Triumph of Christianity: How the Jesus Movement Became the World's Largest Religion

Cities of God: The Real Story of How Christianity Became an Urban Movement and Conquered Rome

God's Battalions: The Case for the Crusades