The shortest principal Upanishad — twelve verses on the syllable Om and the four states of consciousness (waking, dreaming, deep sleep, and Turīya). The basis of Advaita Vedānta.
1 chapter
Tradition
Śruti. Belongs to the Atharva Veda. The Māṇḍūkya Kārikā of Gauḍapāda (c. 7th century CE) is the earliest systematic Advaita commentary on it.
Translation
R. E. Hume, *The Thirteen Principal Upanishads* (Oxford University Press, 1921). Public domain.
License
Public domain (pre-1929 English translation). Reproduced for educational and religious commentary.