This chapter explores the life and legacy of Abū al-Qāsim al-Junayd al-Baghdādī (d. 298/910), emphasizing the pressing need for a comprehensive and innovative study accessible to both specialist and non-specialist audiences. It delineates the objectives, scope, and methodological framework of the book, provides an overview of the corpus of sources consulted, and concludes with a detailed outline of the chapters to follow.