The Upanishads are called shruti, revelations. Mandukya Upanishad, though the shortest of all Upanishads, is a most revered, profound Upanishad that teaches us how to know four states of consciousness: the waking, dreaming and sleeping states, and turiya, the fourth state, beyond the first three. In this Upanishad, there is a unique combination of psychology and profound philosophy; a clear exposition and understanding of the four states of consciousness.
About the Author:
Swami Rama was born Brij Kishore Dhasmana, to a Northern Indian Brahmin family and became lineage holder of the Sankya Yoga tradition of the Himalayan Masters. He was raised in the Himalayas by his master Bengali Baba, and, under the guidance of his Master, traveled from monastery to monastery and studied with a variety of Himalayan saints and sages, including his grandmaster who was living in a remote region of Tibet. From 1949 to 1952 held the prestigious position of Shankaracharya of Karvirpitham in South India. After returning to Bengali Baba in 1952 and many years of further practice in the Himalayan caves, Swami Rama was encouraged by his teacher to go to the West where he spent a considerable portion of his life teaching, specifically in the United States.
Swami Rama is especially notable as one of the first yogis to allow himself to be studied by Western scientists. In the 1960s he allowed himself to be examined by scientists at the Menninger Clinic who studied his ability to voluntary control bodily processes (such as heartbeat, blood pressure, body temperature, etc.) that are normally considered to be non-voluntary.