"The Hindu-Yogi Science of Breath" is a book written by Yogi Ramacharaka, a pseudonym for William Walker Atkinson, an American author, and publisher who lived in the late 19th and early 20th centuries. The book provides a comprehensive guide to the science of breath control and its impact on physical and mental health. The book begins by exploring the basics of breathing, including the anatomy of the respiratory system and the mechanics of inhalation and exhalation. It then goes on to discuss the relationship between breath control and the nervous system, and the ways in which breathing can be used to promote relaxation, reduce stress and enhance mental clarity. Throughout the book, Yogi Ramacharaka presents a range of practical exercises and techniques for controlling the breath, including deep breathing, alternate nostril breathing, and various types of pranayama. "The Hindu-Yogi Science of Breath" is a valuable resource for anyone interested in the science of breath control and its impact on physical, mental, and spiritual health.