The Mandukya Upanishad is the shortest of the Upanishads. It is in prose, consisting of twelve verses expounding the mystic syllable Aum, the three psychological states of waking, dreaming and sleeping, and the transcendent fourth state of illumination. This Upanishad has been greatly extolled. The Muktikopanishad, which discusses other Upanishads, says that the Mandukya Upanishad alone is enough for salvation.
Gaudapadacharya was the author of Māṇḍukya Kārikā, a commentary on Mandukya Upanishad. It was written in 8th century CE and is one of the earliest works on Advaita Vedanta.
About the Upanishad
The name, "Mandukya" may have come about for several reasons:
Attribution to a sage called Manduka. Manduka means "son of Manduki" and a seer with this metronymic is mentioned in the Brihadaranyaka Upanishad along with the Mandukeyas, his disciples. The Mandukeyas figure in the Bhagavata Purana as the receivers of a branch of the Rig Veda from Indra. This group of seers also figures in the Rig Veda itself: their hymns are mostly connected with lingustics. A text on the etymology of Vedas with the name "Manduki Shiksha" deals with the notes of the musical scale.
Manduka is also a type of yoga – a "particular kind of abstract meditation in which an ascetic sits motionless like a frog". Mandukasana is one of the asanas (postures) described in yoga.