"This book is a historical and sociological reading of the relation between Sunnis and Shias from the inception of the dispute for Mohammed's succession until today. It is divided in two parts. The first part offers a comprehensive history of the divide. It shows how Shiism was, during much of the Middle Ages, the main contestation ideology of the caliphate, but also how Sunnism and Shiism converged as Shiism progressively ceased to be an esoteric...