Although prayerfulness and the remembrance of God suffuse all the formal practices of Islam, there are times when the Muslim simply 'sits alone with his Lord' to repeat formulas drawn from the Qur'an and the sayings of the Prophet, seeking remission of his sins and the purification of his heart. The present volume is probably the most widely read compendium of such material, popular not only for its comprehensiveness and beauty, but also for the analytical approach of its author, who explores the psychological and spiritual effects of prayer and the celebration of God's name. The original translation by Kojiro Nakamura, now Head of the Islamic Studies Department at the University of Tokyo, has been substantially revised and augmented with 'hadith' identification.