Why do large numbers of people meet in St. Peter's Square every year to celebrate Mass on Easter Sunday? What accounts for the controversy about the refusal of a high-profile sports figure to stand for the national anthem at each of his team's games? Why did the members of a large religious community commit suicide at the direction of their maniacal leader? How do warriors rationalize going into battle in the face of possibly being severely injured or killed? What is the role of followers ...