奥义书——吠陀传统的哲学核心，阐明梵、真我、知识、行动与解脱的本质。十部主要奥义书，另加精选的毗湿奴派小奥义书。
The "unsupported" book: a series of questions and short answers on who Brahman is, what caste is, what action is. It ends with all this being known not by one's own mind, but by the grace of a teacher.