"This modern study on bid'ah - or heretical innovation - critically explores the boundaries of normative Islam and outlines the legal debate surrounding the subject. It examines the influence of foreign elements in Islamic thought, focusing on corrupt religious practices, as well as distorted beliefs, acts of worship and customary practices pertaining to religious expression. Muhammad al-Ghazali also argues for a 'Sufi core' in the reformist tradition, but one that has been stripped of the foreign accretions that have corrupted many Sufi movements."