Baldwin of Bourcq left his home in France in 1096 to join the great crusade summoned by Pope Urban II for the liberation of the holy sites and Christian peoples of Syria and Palestine from the domination of the Muslim Turks. In 1100 he became ruler of the Franco-Armenian county of Edessa. In 1118 he succeeded to the kingdom of Jerusalem. In just over two decades this younger son of a minor French count had become one of only a dozen kings in Western Christendom. To defend the principalities of Outremer against their Turkish and Egyptian enemies he travelled thousands of miles and led his troops in over two dozen campaigns. He spent two extended periods in Turkish captivity, yet he outlived almost all of his fellow crusaders, and died leaving the succession to his kingdom secure. This is the first biography in any language of a remarkable man. Drawing on a wide range of narrative and documentary sources, it gives an account of Baldwin's ancestry and life from his first recorded appearance up to his death in 1131. It explains the complex and shifting geopolitics of the principalities of Outremer and the Muslim territories around them, and explores Baldwin's character as a ruler and leader in war, the significance of his wide-ranging kinship network, and the succession to the kingdom of Jerusalem. Baldwin of Bourcq will appeal to students, teachers and researchers in Medieval History, especially Crusade Studies and Military History.