Here we examine four facets of yoga as a form of mind-body discipline. These include systems of yoga, including aṣṭāṅgayoga, ṣaḍaṅgayoga, the “threefold yoga” of karma, bhakti, and jñānayoga, and the “fourfold yoga” of mantra, laya, haṭha, and rājayoga. We look at the tension between worldly and otherworldly dimensions of yoga; links within yoga traditions that extend from ancient Vedic practices to contemporary postural traditions of yoga; and the connections between contemporary technology-driven “biohackers” and their forerunners within the Indic yogic and ascetic traditions.