Holotropic Breathwork: A New Experiential Method of Psychotherapy and Self-Exploration by Stanislav Grof (2014)

Conducted 35,000 sessions
More testimony to the importance of Esalen (lot of the work done there, 1 month long sessions). Real inspiration for the Hubs.

Excerpts

The Course of Holotropic Sessions

Emotional qualities span a wide spectrum and intensity can transcend anything even imagined in everyday consciousness

The emotional qualities observed in holotropic sessions cover a very wide range. On one side of the spectrum, one can encounter feelings of extraordinary well-being, profound peace, tranquillity, serenity, bliss, cosmic unity, or ecstatic rapture. On the other side of the same spectrum are episodes of indescribable terror, consuming guilt, or murderous aggression, and a sense of eternal doom. The intensity of these extraordinary emotions can transcend anything that can be experienced or even imagined in the everyday state of consciousness. These extreme emotional states are usually associated with experiences that are perinatal or transpersonal in nature.

Note esp that sentence:

The intensity of these extraordinary emotions can transcend anything that can be experienced or even imagined in the everyday state of consciousness.

This is kind of amazing. Imagine this sort of thing were really mainstream.