This book provides an in-depth analysis of two Islamist parties in Pakistan: the highly influential Jama'at-e-Islami; and the more militant Jama'at-ud-Da'wa, widely blamed for the November 2008 terrorist attack in Mumbai, India. Basing findings on thirteen months of ethnographic work with the two parties in Lahore, it proposes that these Islamists are involuntarily facilitating secularization within Muslim societies, even as they vehemently oppose secularism. The book offers an account of the workings of both parties that challenges received ideas about the relationship between the ideology of secularism and the processes of secularization. It particularly illuminates the impact of women on Pakistani Islamism, while arguing that these Islamist groups are inadvertently supporting secularization by forcing a critical engagement with the place of religion in public and private life. The book highlights the role that competition among Islamists and their focus on the state as the center of their activity plays in assisting secularization.