In the Bardo Thodol, (The Tibetan Book of the Dead) what is nominally called the "Bardo", is that series of states after death and before rebirth during which the dying person will encounter a light, visions and encounters with deities and processes leading to rebirth.

Dying is usually caused by hypoxia or cessation of breathing and the cutting off of oxygen to our bodies. There are techniques by which someone can induce hypoxia through the discipline of Pranayama to voluntarily and consciously enter the Bardo realms (Tantric practices), but as this book is in the public domain and as this is obviously a dangerous if not deadly path, I have chosen not to reveal any of these methods.