The Prashna or Prasna Upanishad (प्रश्न उपनिषद् or प्रश्नोपनिषद्) is one of the main or primary Upanishad and is part of Atharva Veda. In Sanskrit, "Prashna" means question. This Upanishad contain six questions and their answers, wherein except first and last questions, all other questions are a group of smaller sub-questions.
Six students interested in knowing about Brahman visit Sage Pippalada and present their doubts. Instead of answering them immediately, Pippalada asks them to take up penance, follow Brahmacharya, and stay at his place for one year. Upon completion of the year, he answers their questions. Prasnopanishada has six chapters, each containing question by one student and Pippalada's answer.
The six students were:
1. Sukesha, the son of Bharadwaja
2. Satyakama, the son of Shibi
3. Sauryayani, the descendant of Garga
4. Kausalya, the son of Ashwala
5. Bhargava, from Vidarbha and belonging to lineage of Sage Bhrigu
6. Kabandhi, the son of Katya
The 1st question by Kabandhi throws light on the root cause of the universe. The 2nd question by Bhargava deals with the supremacy of Prana over other organs of human being. The 3rd question by Kausalya deals with the origin and functioning of Prana. With 4th question, Sauryayanee highlight Dream world of a sleeping person. The 5th one from Bhargava concerns with fruits of Aum or Om's meditation. The last question tells about creator of universe, who has sixteen vital things (kala).
To make this complicated topic as simple as possible, we have combined material from two of Yogeshwarji's books 1. Upanishad nu Amrut (Articles) and 2. Dus Upanishad (Poetic Translation) (Unpublished). We hope that you will like it.