This seminal work by Abu Abd al-Rahman al-Sulami is one of the earliest and most important sources on the history of Islamic mysticism. The book is composed of two parts: the first, 'History of the Sufis,' provides invaluable biographical accounts of the lives, teachings, and spiritual lineages of early Sufi masters. The second part, 'The Trials of the Sufis,' delves into the hardships, persecutions, and social challenges these spiritual figures endured, offering a comprehensive view of the formative period of Sufism.