From infallible Imams to Ayatollahs in Iran, Shi'ism has long been a prominent, if misunderstood, branch of Islam. It regards Ali, Muhammad's son-in-law, as the Prophet's legitimate successor. But theological differences between the Shi'ah and Sunni Muslims have led to sectarian violence, massacres and the desecration of holy sites. In this Beginner's Guide, Dr Moojan Momen offers an accessible and comprehensive overview of Shi'ism, tracing the history of the community, its leadership and doctrines, from its inception to modern times. Packed with useful tables, family trees and text boxes, this engaging and up-to-date guide is a perfect introduction to the historical and geopolitical causes of religious tensions still troubling the Middle East today.