Vivekananda's Ninth Auxiliary

In his influential 1896 book Raja Yoga, Swami Vivekananda redefined Patanjali's aṣṭāṅga system by inserting a subsidiary auxiliary under the rubric of prāṇāyāma, calling it The Psychic Prana. In doing so, he incorporated the tantric and haṭhayogic concepts of cakras and kuṇḍalinī into Patanjali's classical system, creating a synthesis for the modern age. This paper examines the details and context of Vivekananda's modifications.