The Yoga Sutras are the aphorisms of yoga codified by Patanjali and considered an authoritative and seminal text of classical yoga. The word ‘sutra’ literally means a compressed string of information. The Yoga sutras consist of 126 sutras divided into four padas or chapters: Samadhi pada, the chapter on defining the the goal and core concepts of yoga; Sadhana pada, the chapter on the practice and techniques of yoga; Vibhuti pada, the chapter on the attainments or supernormal powers one can develop in yoga and the Kaivalya pada, the chapter on attaining the goal of yoga.
The Yoga sutras can be regarded as a manuel of Yoga because of how clearly it delinates the path of Yoga from start to finish, identifying the stages and the possible obstacles and tips to overcome them. It also lays the foundation for all the main forms of yogas: Raja yoga, Kriya yoga, Karma yoga and Bhakti yoga. It is also considered core reading on most Yoga courses, including the Yoga Alliance, USA.