It is among the 31 Upanishads associated with the Atharvaveda,  and one of the Samanya Upanishads. In this Upanishad, Atharvangiras to whom the  Atharvaveda is attributed, extols the virtues of Surya, the Sun-god, calling him the ultimate truth and reality Brahman. Surya, asserts the text, is the creator,  protector, and destroyer of the universe, and the Sun-god is identical to one’s  Atman (soul, self).  

The Surya Upanishad opens by stating that its objective is to explain and state the  Atharvaveda mantra for the Sun. Bramha is the source of the Surya mantra, asserts the text, its poetic meter is Gayatri, its god is Aditya (sun), it is Hamsas so’ham– literally, “I am he” – with Agni(fire), and Narayana (Vishnu) is the Bija  (seed) of this mantra. This mantra aims to remind and help win the reciter of the four worthy human goals – Dharma (ethics, duties to self and others,  righteousness), Artha (prosperity, wealth, means of life), Kama (pleasure,  emotions, love), and Moksha (liberation, freedom, spiritual values).