This document provides an introduction to yoga, covering its physiological, psychological, and philosophical aspects. It discusses different types of yoga including hatha yoga, which uses physical exercises and breathing techniques; laya yoga and kundalini yoga, which focus on psychic energy; mantra yoga, which uses repetition of words; and jnana yoga, bhakti yoga, karma yoga, which control thought, emotion, and action respectively. Raja yoga integrates all six approaches. Ashtanga yoga outlines an 8-step path including yama, niyama, asana, pranayama, pratyahara, dharana, dhyana, and samadhi. Regular yoga practice can