Vedanta, along with Sankhya, Yoga, Nyaya, Vaisheshika, and Mimamsa, is one of the six Hindu theist philosophies. It focuses heavily on the Upanishads, which center concepts such as Brahman (ultimate reality) and Atman (soul, self).In Plato and Vedic Idealism, which was first published in 1924, Swami Paramananda explores similarities between Greek philosophy, with emphasis on Plato, and Vedic philosophy.