The Taittiriya Upanishad speaks of levels of bliss that can be experienced – from simple pleasure to unexcelled bliss – and the idea that existence is inherently blissful (ananda). Spiritual life consists in discovering the culmination of bliss, which is inherent in the Absolute (Brahman). This scripture also contains the first reference to the doctrine of the five “sheaths” (koshas), of which the fifth and final sheath is composed of pure bliss. Here (II.4.1) we also find the first recorded mention of the word Yoga in the technical sense, as the conscious control of the fi ckle senses (indriyas).