Hatha Yoga, is also known as hatha vidya or the "science of hatha" yoga. The word Hatha comes from combining the two Sanskrit terms "ha" meaning sun and "tha" meaning moon. The word "ha" refers to the solar nadi (pingala) in the subtle body and "tha" the lunar channel (ida). However, when the two components of the word are placed together, "hatha" means "forceful", implying that powerful work must be done to purify the body. Yoga means to yoke, or to join 2 things together, hence hatha yoga is meant to join together our sun (masculine, active) energy with our moon (feminine, receptive) energy, thus producing balance and greater power in an individual.
Traditional Hatha Yoga is a holistic yogic path, including moral disciplines, physical postures asanas, purification procedures shatkriyas, poses mudras, yogic breathing pranayamas and meditation. The Hatha yoga predominantly practiced in the West consists of mostly asanas understood as physical exercises.
This book teaches the correct way to breath, includes many breathing exercises and yoga exercises, along with suggestions on diet, relaxation and sleep.