This document discusses the importance of breathing and respiration from both a scientific and yogic perspective. It covers:
1) The role of the respiratory system in exchanging gases between the atmosphere, blood, and cells. Respiration occurs at the cellular and organism levels.
2) Yogic concepts of prana as the universal life force and different levels of pranic manifestation from minerals to humans. Pranayama involves controlling prana through breath control techniques.
3) Details of respiratory anatomy and the mechanics of breathing. It also discusses how pranayama techniques can balance the breath and expand awareness.