Little is known in the West about the division of the Islamic world into Shiites and Sunnites and even less about the stratification of these two groups, with most of the attention going to the Sunnites. Moosa’s comprehensive study of the origins and cultural aspects of the different extremist, or Ghulat, Shiite sects in the Middle East is a ground-breaking work. These sects whose ‘extremism’ is essentially religious are generally a peaceful people and, except for the Nusayris of Syria, are not political activists.