Buddhism has a wide range of sacred texts and scriptures. In Theravada Buddhism, the Pali Canon contains the Buddha's teachings in three groups of writings, known as the “Three Baskets” (Tipitaka). The Vinaya Pitaka (discipline basket) contains precepts for monks and nuns; the Sutta Pitaka (teaching basket) contains the discourses of Buddha; and the Abidhamma Pitaka (metaphysical basket) contains Buddhist theology. Mahayana Buddhism reveres the Pali Canon as a sacred text, but adds to it the sutras, written between 200 BCE and 200 CE, which reflect distinctively Mahayana concepts. There are over two thousand sutras, but some texts, such as the Lotus Sutra and Heart Sutra, are important to most branches of Mahayana. The Book of the Dead is the Tibetan text most well known to the West, describing in detail the stages of death from the Tibetan Buddhist point of view. Zen, a branch of Mahayana Buddhism, rejects scripture altogether in its early stage.