"The Mystics of Islam" by Reynold A. Nicholson is a scholarly exploration of Islamic mysticism, or Sufism, and its history, teachings and practices of Islam. The book covers the early development of Sufism in the Islamic world, the emergence of distinct Sufi orders and their doctrines, and the evolution of Sufi poetry and literature. Nicholson discusses various aspects of Sufi mysticism, such as its emphasis on the direct experience of Almighty, the importance of spiritual guides and the process of spiritual purification, the use of meditation and ecstatic practices, and the concept of love as the central theme of Sufi spirituality. The book also examines the lives and teachings of prominent Sufi figures, such as Rumi, Ibn al-ʿArabī, and Ghazālī, and their contributions to Islamic philosophy and spirituality. Nicholson's writing provides an objective and nuanced portrayal of Sufism, dispelling common misconceptions and highlighting its enduring impact on Islamic culture and spirituality. Overall, "The Mystics of Islam" is a comprehensive and insightful introduction to Islamic mysticism, written with both academic rigor and a deep appreciation for the spiritual dimensions of Sufi thought and practice.