Praying and Fasting by Hayo de Vries , writer, author and theologian, with over 55000 students, explores the transforming power of prayer and fasting through clear biblical teaching and practical application. As director of 50Days of Discipleship , Hayo De Vries equips believers and churches to experience spiritual renewal and intimacy with God. This study combines theological depth with accessible guidance, making it ideal for personal devotion, small‑group study, or church training.