The Arabian religious reform movement of the 18th and 19th centuries, known in the West as Wahhabism, is one of the most controversial and misunderstood religious movements of the modern Middle East. This biography of its founder, Muhammad ibn Abd al-Wahhab, is the first serious English-language account written not from a Western, but an Arabian perspective. Based on exhaustive research of primary sources, 'Abd-Allah Salih al-'Uthaymin reconstructs the social, political and spiritual environment of the Arabian peninsula in the time of Ibn Abd al-Wahhab. The author charts this movement's intellectual development and growing sway, and unpicks the historic alliance of its founder with the House of Al Sa'ud: a uniquely close partnership of political and religious relationships whose legacy is felt in the Saudi state to this day. Al-Uthaymin also provides a detailed exposition and commentary on Ibn Abd al-Wahhab's doctrines, based on his published and unpublished works, and explains his perspective on concepts such as tawhid, takfir and sharia. This meticulously researched biography offers a unique insight into its complex and often controversial subject. As such, it will become essential reading for anyone interested in political Islam, Saudi Arabia and the modern Middle East.