The Tibetan Book of the Dead, known as 'Bardo Thodol' in Tibetan, is a spiritual text that provides guidance for the dying and the deceased on navigating the afterlife and the process of rebirth. This text is rooted in Tibetan Buddhism and is closely associated with various schools and lineages, particularly Nyingma, which emphasize the importance of understanding the bardo states—transitional phases between death and rebirth.