Prashna Upanishad (IAST praṣnopaniṣad) is one of the older, "primary" Upanishads commented upon by Shankara. It is a Mukhya Upanishad, associated with the Atharvaveda. It figures as number 4 in the Muktika canon of 108 Upanishads.

In Sanskrit, Prashna mean question. This book consists of six questions and their answers, hence the name. It is in the form of question-answers.except first and last questions, all other questions are actuallya group of smaller sub-questions.As narrated in the beginning of this Upanishad, Six pupils interested in knowing divinity or Brahman come to sage Pippalada and ask questions of great spiritual importance. Pippalada asks them to take up penance of one year. Upon completion of penance, they again come to sage and ask questions, then the sage answers their questions.

The pupils who ask questions are:

1. The son of Bharadwaja the Sukesha
2. The son of Shibi the Satyakama
3. The desendant
   
   
   
   of Garga the Sauryayanee
4. The son of Ashwalayana the Kausalya
5. Bhargava of the country of Vidarbha
6. The son of Katya the Kabandhi

Each of them asks one question to Pippalada and answer(s) to it forms a chapter in the Upanishad.

The questions

The first question is asked by Kabandhi concerned with the root cause ofthe of the universe.

The second question asked by Bhargava is concerned with the supremacy of vital Force of Life or Prana over other sense organs of human being.

The third question asked by Kausalya is concerned with the origin and functioning of Vital Force of Life.

The fifth question is concerned with fruits one gets by meditating on holy syllable OM.

The sixth and last question is concerned with the being by whom all this known-unknown universe got created and who is equipped with sixteen vital things (kala) or who is called as Shodasha Kala Purusha.