The Yogi Science of Breath

Yogi Ramacharaka's 1903 text The Hindu-Yogi Science of Breath: A Complete Manual of the Oriental Breathing
Philosophy of Physical, Mental, Psychic, and Spiritual Development discusses both Western and Eastern breathing philosophy in plain English. These teachings come from adepts and yogis, but Ramacharaka's fluid writing caters to the layman

This empowering work helps readers to understand the power of this everyday - and often ignored - practice.
The classic guide covers everything from the esoteric theories of breath to the emotional, mental, physiological,
psychic, and spiritual aspects of breathing, along with exercises to develop them.

Ramacharaka's ideas merit attention - even today - not because they are a "secret science," but because so many of them work. Famed trumpet player Maynard
Ferguson identified it as an early influence on his decision to adopt yogi deep breathing techniques, and later claimed that it revolutionized the way he approached the trumpet. Among many musicians, swimmers, martial artists, fitness gurus, yoga practitioners, endurance runners,
and holistic healers, The Yogi Science of Breath is considered an indispensable reference guide and tool.