This book examines the nature and development of al-Hajj 'Umar's reform movement in the Western Sudan (1830-1864). The outburst of militant reform movement in the area during the 19th century has attracted the attention of several scholars in the field of African studies. The movement is traced from its peaceful religious beginnings to its final militant conclusion. Today, one can speak of three types of reform or resistance against the Western colonial domination in Western Sudan: (1) hard or militant; (2) soft, but confrontational; and (3) soft, reconciliatory, but highly intellectual. All these types of reform hinge on the legacy and the role of al-Hajj 'Umar's Sufi orientation. His role in initiating and conducting the reform as well as its socio-economic circumstances under which the movement took place are given special consideration in the study. The purpose of the book is to provide a balanced perspective of al-Hajj 'Umar's style of reform. This is conducted through al-Hajj 'Umar's own writings and actions alongside those of his contemporaries. Thus, we are able to establish the link between his Sufi beliefs, practices and the subsequent militant reforms in the area.