Several versions of the Hamsa Upanishad exist, of which the Calcutta and Poona editions have been most studied. The layout and some verses vary, but the message is similar. The text is listed at number 15 in the serial order of the Muktika enumerated by Rama to Hanuman in the modern era anthology of 108 Upanishads. It is also called the Hamsopanishad.
