Yogatatva Upanishad
Yogatattva Upanishad is a minor Upanishad from Krishna Yajur Veda. It has 142 metrical verses. Yogatattva Upanishad describes four major types of Yoga: Mantra yoga, Laya Yoga, Hatha Yoga and Rajayoga. Proper intonation of sound is basic to Mantra Yoga. Laya Yoga is contemplating on the lord, while doing all activities, and even while sleeping. Hatha Yoga is the practice of eight fold yoga of patanjali: yama, niyama, asana, pranayama, pratyahara, dharana, dhyana and samadhi. When discrimination and indifference (Viveka and Vyraghya) is achieved, a yogi can proceed to Rajayoga. The Upanishad has lot of practice classes on yoga and meditation. Saguna and Nirguna meditation is separately discussed.