According to Bhagavad Gita, one of the most sacred texts of Hinduism, the subtle body is composed of mind, intelligence and ego, which controls the gross physical body. It is also known in other different spiritual traditions: "the most sacred body" (wujud al-aqdas) and "true and genuine body" (jism asli haqiqi) in Sufism, "the diamond body" in Taoism and Vajrayana, "the light body" or "rainbow body" in Tibetan Buddhism, "the body of bliss" in Kriya Yoga, and "the immortal body" (soma athanaton) in Hermeticism. The various attributes of the subtle body are frequently described in terms of often obscure symbolism: Tantra features references to the sun and moon as well as various Indian rivers and deities, while Taoist alchemy speaks of cauldrons and cinnabar fields.
The expression "subtile body" appears suddenly in English literature in about 1650, appears erratically until it ceased to be used by about 1840. At that time, the more common term "subtle body" comes into use. The latter expression gradually gains in currency through the nineteenth century, and begins a sharp increase in usage from about 1940 until the present time. Further research is needed to clarify the actual authors who used the phrase, and what they meant by it. But the word may have a connection with the Sanskrit Sūkṣma (subtle, unmanifest, dormant) Śarīra (body) which is described in the Vedas.
The Yogic, Tantric and other systems of Hinduism, Vajrayana Buddhism, as well as Chinese Taoist alchemy contain theories of subtle physiology having a number of focal points (chakras, acupuncture points) connected by a series of channels (nadis, meridians) that convey subtle breath (prana, vayu, ch'i, ki, lung).
These invisible channels and points are understood to determine the characteristics of the visible physical form. By understanding and mastering the subtlest levels of reality one gains mastery over the physical realm. Through practice of various breathing and visualization exercises one is able to manipulate and direct the flow of vital force, to achieve supernormal powers (Sanskrit: siddhis) and attain higher states of consciousness, immortality, or liberation.
Early mentions of subtle body (Sanskrit: sūkṣma śarīra) concepts appear in the Upanishads, particularly the earliest known theory appears in the Taittiriya Upanishad's (circa 4th or 5th centuries BCE) theory of five bodies or selves. The Taittiriya differentiates between five increasingly subtle body/selves: