The study of death is key to understanding mental processes. Without close acquaintance with the experience of death and the process of death-rebirth, it is impossible to understand religion, mysticism, shamanism, and mythology. According to various mystical schools, people who survive death or mortal danger and return to life are called twice-born. Contact with death changes the attitude towards it, regardless of whether this contact is purely symbolic or occurs in reality, for example, as a result of accidents or during events leading to real clinical death.

Stanislav Grof ( Stanislav Grof, born 1931) is an American psychologist and psychiatrist of Czech origin, Doctor of Philosophy in Medicine, founder of transpersonal psychology, one of the pioneers in the study of altered states of consciousness.