The Brihadaranyaka Upanishad is one of the oldest Upanishads and one of the largest and important ones, according to . It was written by Ajnavalkya in the mid-first millennium BCE. Brhadaranyaka Upanishad means the “great forest-book” – meaning that is should be read in solitude – and it consists of three part called kandas: the Madhu kanda, the Yajnavalkya or the Muni kanda and the Khila kanda. The text present various methods of meditation and a number of rites and rituals. Brhadaranyaka Upanishad concludes by describing the three virtues that one should practice: self-restraint, giving, and compassion.