Patanjali's Eight Limbs of yoga practice are:

1. Yama (The five "abstentions"): violence, lying, theft, (illicit) sex, and possessions
2. Niyama (The five "observances"): purity, contentment, austerities, study, and surrender to god
3. Asana: Literally means "seat", and in Patanjali's Sutras refers to seated positions used for meditation. Later, with the rise of Hatha yoga, asana came to refer to all the "postures"
4. Pranayama ("Breath Control"): Control of prana or vital breath
5. Pratyahara ("Abstraction"): Reversal of the sense organs
6. Dharana ("Concentration"): Fixing the attention on a single object
7. Dhyana ("Meditation"): Intense contemplation of the true nature of reality
8. Samadhi ("Liberation"): Super-conscious state of enlightenment

Hatha Yoga Pradipika

Hatha Yoga is a particular system of Yoga introduced by Yogi Swatmarama, a yogic sage of the 15th century in India, and compiler of the Hatha Yoga Pradipika. Hatha Yoga is a development of - but also differs substantially from - the Raja Yoga of Patanjali, in that it focuses on shatkarma, the purification of the physical as leading to the purification of the mind (ha) and prana, or vital energy (tha). In contrast, the Raja Yoga posited by Patanjali begins with a purification of the mind (yamas) and spirit (niyamas), then comes to the body via asana (body postures) and pranayama (breath). Hatha yoga contains substantial tantric influence, and marks the first point at which chakras and kundalini were introduced into the yogic canon. Compared to the seated asanas of Patanjali's Raja yoga which were seen largely as a means of preparing for meditation, it also marks the development of asanas as full body 'postures' in the modern sense.

Hatha Yoga in its many modern variations is the style that most people actually associate with the word "Yoga" today. Because its emphasis is on the body through asana and pranayama practice, many western students are satisfied with the physical health and vitality it develops and are not interested in the other six limbs of the complete Hatha yoga teaching, or with the even older Raja Yoga tradition it is based on.

Other Works

The sage Sri Nathamuni supposedly composed the Yoga-Rahasya in the 9th or 10th century CE, although no copies of this work are known to exist. Sri Tirumalai Krishnamacharya claimed to have received knowledge of this text in a vision. Krishnamacharya is also responsible for the only known translation of the Yogayajnavalikya Samhita, a dialogue between the great sage Yajnavalkya and his learned wife Gargi. Like the Gheranda Samhita and the Hatha Yoga Pradipika, the Yogayajnavalikya Samhita is generally considered a tantric yoga work.