""What Is Yoga?"" is a book written by P. D. Ouspensky that explores the ancient practice of yoga. The book provides a comprehensive overview of the philosophy and principles of yoga, including the various types of yoga, the benefits of practicing yoga, and the spiritual aspects of the practice. Ouspensky also delves into the history of yoga and its origins in ancient India, as well as the evolution of yoga over time. The book is written in a clear...