This book is an introduction to the literature and thought of the founders of the Shaykhiyya and the Babiyyah, two important religious movements in nineteenth-century Iran. The first part is an overview of the thought of Ahmad al-Ahsa?i and Kazim ar-Rashti, the progenitors of the Shaykhiyya, with a focus on their religious and philosophical teachings. The second part is an analysis of the early writings of ?Ali-Muhammad Shirazi (the Bab), the initiator of the Babiyyah. It contains a survey of major concepts found in his works and addresses issues that have generated debate in the past, particularly the exact nature of his religious claim and its reception by his contemporaries. Finally, the book contains an edition of the Bab's Treatise on Specific Prophethood. This is the first scholarly edition of a work by the Bab to be published in the original language.