The foundational text of the Yoga darśana, and the first systematic exposition of yoga, attributed to Patañjali. The composite text may well be the result of editorial inclusiveness, since it seems to recommend at least two different types of yoga. Its 194 (or 195) sūtras are divided into four pādas. The first of these (51 sūtras) deals with samādhi (‘absorbed concentration’), and the general means to attaining it in the context of Sāṃkhya metaphysics. Pāda two (55 sūtras) deals with sādhanā (‘practice’—i.e. the specific means to attainment), including both kriyā- and aṣṭāṅga-yoga. Pāda three (54 or 55 sūtras), entitled vibhūti, deals with the ‘inner limbs’ of aṣṭāṅga-yoga, viz. dhāraṇā (concentration), dhyāna (meditation), and samādhi (absorbed concentration), and (in Vyāsa's commentary, at least) with the supernormal powers (siddhis) generated as epiphenomena of the practice. Pāda four (34 sūtras) deals with the attainment and nature of kaivalya (liberation).
The commentary which has done most to shape understanding of the Yoga Sūtra, particularly in a Sāṃkhya context, is the earliest to survive, the Yogabhāṣya of Vyāsa. This gave rise, in turn, to the Tattvaiśāradī gloss of Vācaspati Miśra, and Bhojadeva's Bhojavṛtti. The Yoga Sūtra also attracted commentators from the Vedānta darśana, including the Yogabhāṣyavivaraṇa subcommentary on Vyāsa, attributed to Śaṅkara, and the longest sub-commentary of all, the Yogavārttika of Vijñānabhikṣu. Commentaries of all kinds, now including many in Western and other non-Indian languages, continue to be written on this important text.