The Māṇḍūkya Upaniṣad (Sanskrit: माण्डूक्य उपनिषद्, Māṇḍūkya Upaniṣad) is the shortest of all the Upanishads, and is assigned to Atharvaveda

It is listed as number 6 in the Muktikā canon of 108 Upanishads

It is in prose, consisting of twelve short verses, and is associated with a Rig Vedic school of scholars

It discusses the syllable Aum; presents the theory of four states of consciousness; and asserts that Aum is Brahman – which is the Whole – and that Brahman is this self (ātman)

The Mandukya Upanishad is notable for having been recommended in the Muktikā Upanishad, through two central characters of the Ramayana, as the one Upanishad that alone is sufficient for knowledge to gain moksha, and as first in its list of eleven principal Upanishads

The text is also notable for inspiring Gaudapada’s Karika, a classic for the Vedanta school of Hinduism

The Mandukya Upanishad is among the often cited texts on chronology and the philosophical relationship between Hinduism and Buddhism