Swami Sivananda Saraswati of Rishikesh wrote with extraordinary productivity throughout his life — over 300 books covering yoga, Vedānta, Āyurveda, and devotional practice. The Science of Prāṇāyāma is among the most frequently reprinted of his technical texts, and for good reason: it covers the practical instruction on breath control with the systematic thoroughness that characterises Sivananda's best work, moving from the foundational understanding of prāṇa and nāḍī through the specific prāṇāyāma techniques with detailed instruction for each. The book opens with philosophy — the Vedic and Upaniṣadic understanding of prāṇa as the life-force underlying all biological function, the nāḍī system of subtle channels through which prāṇa moves (the three principal nāḍīs: iḍā, piṅgalā, and suṣumnā), and the classical teaching on…