But what exactly is Wahhabism? This question drove Valentine to live in the Kingdom for three years, familiarising himself with its distinct interpretation of Islam. His book defines Wahhabism and Wahhabi beliefs and considers the life and teaching of Muhammad ibn Abd’al Wahhab and the later expansion of his sect. Also discussed are the rejection of later developments in Islam such as bidah; harmful innovations, among them celebrating the prophet’s birthday and visiting the tombs of saints; the destruction of holy sites due to the fear of idolatry; Wahhabi law, which imposes the death sentence for crimes as archaic as witchcraft and sorcery, and the connection of Wahhabism with militant Islam globally.