The Tibetan Book of the Dead, so called, is known as the Bardo Thodol in Tibetan. An alternate translation of the title gives us something like the Book of Instructions for the In-between States.
Generally, that means death. Traditionally, 49 days pass between death and reincarnation in a new body, and the Bardo Thodol gives instructions on how to handle the in-between state and not be tempted by the illusory beautiful and hideous deities and visions.
But bardo need not occur at death. Other events may trigger it. At certain points in life, too, one may enter a bardo, an in-between state, when the linearity of consciousness slips, when the record jumps, when you have the opportunity to catch the right wave to a new level of frequency. To peel away one more layer from prime reality. (The alternative, then... is to drop back into the same programmed pattern.)
Emerging stripped clean, zeroed, nulled, emerging once more into physical reality and time and the surprising sensation of being alive and existing in time, I feel I may be in a bardo state. May Avalokiteshvara the Buddha of Compassion help me keep my mind on the true light, and bless all of you beautiful people. Aum Mani Padme Hum.