The Upanishads are a special type of scripture collection in Hinduism. The theoretical basis of Hinduism is discussed in these texts. Another name for Upanishad is Vedanta. Hindus believe that the Upanishads describe the nature of the Supreme Creator or Brahman and the means by which man can achieve moksha or spiritual liberation. The Upanishads are found mainly in the later parts of the Vedas—the Brahmanas and Aranyakas. These were word of mouth in the guru-disciple tradition in ancient times.