The Third Eye and the Pineal Gland
The pineal link is Theosophical: Blavatsky's The Secret Doctrine (1888) called the gland the atrophied remnant of a spiritual third eye. Its best-known popular vehicle, the bestselling 1956 memoir The Third Eye, was exposed in 1958 as the work of Cyril Hoskin, an English plumber's son who had never been to Tibet.
H. P. Blavatsky, The Secret Doctrine, vol. II (1888), pp. 294–301; T. Lobsang Rampa, The Third Eye (1956), exposed in 1958 as the work of Cyril Hoskin
The belief that a small gland at the centre of the brain is a spiritual organ of higher perception, linked to the mystical concept of a 'third eye'.