The events of Sept. 11 left many Americans questioning how such atrocities could be perpetrated in the name of religion: specifically, the religion of Islam. Few Americans know much about Islam, yet it continues to be the fastest growing religion in the US today. What is Islam? What do Muslims believe in? And how does their faith shape their lives, identities and their political ideologies? FRONTLINE explores these and other questions in "Muslims," a special two-hour report that examines the fundamental tenets of Islam and the causes behind its current worldwide resurgence.Through interviews with dozens of ordinary Muslims from such diverse countries as Iran, Malaysia, Turkey, and the U.S., FRONTLINE illuminates the perspectives, conflicts, and tensions that are shaping today's Muslim world.