For the first time, an Upanishad gives numerous and precise details concerning the extraordinary powers gained by practice and meditation. The four chief asanas (siddha, padma, simha and bhadra) are mentioned, as are the obstacles encountered by beginners – sloth, talkativeness, etc. A description of pranayama follows, together with the definition of the matra (unit of measurement for the phases of respiration), and important details of mystical physiology (the purification of the nadis is shown by external signs: lightness of body, brilliance of complexion, increase in digestive power, etc. I relate to you the means to be employed for destruction of errors; Without the practice of yoga, how could knowledge set the Atman free? Inversely, how could the practice of yoga alone, devoid of knowledge, succeed in the task? The seeker of Liberation must direct his energies to both simultaneously. The source of unhappiness lies in Ajnana (ignorance); Knowledge alone sets one free. This is a dictum found in all Vedas. – Yogatattva verses 14–16 It is the Yogatattva that appears to be most minutely acquainted with yogic practices: it mentions the eight angas and distinguishes the four kinds of yoga: Mantra yoga, Laya yoga, Hatha yoga and Raja yoga. Of the ten Yamas, Mitahara (moderate food) is most important. Of the ten Niyamas, O four-faced one, Ahimsa (non-violence) is most important. —Yogatattva Upanishad 28–29 Whatever the Yogin sees with his eyes, he should conceive of all that as the Atman (soul, self). Similarly, whatever he hears, smells, tastes and touches, he should conceive of all that as the Atman. —Yogatattva Upanishad 69–72 Samadhi is that state in which the Jiva-atman (lower self) and the Param-atman (higher self) are differenceless. —Yogatattva Upanishad 107 These three letters "AUM", is no different than the Brahman, by that Yogin in the Turiya-state pervades the entire world of phenomena, in the belief "all this is I alone". That is the Truth. That alone is the transcendent existence, which is the substratum. —Yogatattva Upanishad 135–136 Yogin's relationship with the world At an unprohibited far off place, Calm and quiet, undisturbed, The Yogin guarantees protection, To all beings, as to his own self. —Yogatattva Upanishad 15