Yoga Sutras by Maharshi Patanjali

Patanjali's writing also became the basis for a system referred to as "Ashtanga Yoga" ("Eight-Limbed Yoga"). This eight-limbed concept derived from the 29^th Sutra of the 2^nd book, and is a core characteristic of practically every Raja yoga variation taught today. The Eight Limbs are:

1. Yama (The five "abstentions"): Ahimsa (non-violence), Satya (Truth, non-lying), Asteya (non-covetousness), Brahmacharya (non-sensuality, celibacy), and Aparigraha (non-possessiveness).
2. Niyama (The five "observances"): Shaucha(purity), Santosha(contentment), Tapas (austerity), Svadhyaya (study of the Vedic scriptures to know about God and the soul), and Ishvara-Pranidhana (surrender to God).
3. Asana: Literally means "seat", and in Patanjali's Sutras refers to the seated position used for meditation.
4. Pranayama ("Suspending Breath"): Prāna, breath, "āyāma", to restrain or stop. Also interpreted as control of the life force.
5. Pratyahara ("Abstraction"): Withdrawal of the sense organs from external objects.
6. Dharana ("Concentration"): Fixing the attention on a single object.
7. Dhyana ("Meditation"): Intense contemplation of the nature of the object of meditation.
8. Samādhi ("Liberation"): merging consciousness with the object of meditation.