- Examines in depth the myths, symbology, deities, and beliefs connected to the underworld from many different cultures and mystery traditions

- Investigates the role of the underworld in initiatory rites and mystical practices, such as the Orphic Mysteries, the chambers of reflections in Freemasonry, the cult of the Black Madonna, and the cult of Isis

- Discusses the telluric currents that run through ley lines, the significance of underground waterways, Hollow Earth theory, and the denizens of the subterranean realms, such as dragons, gnomes, and dwarfs

Ancient cultures around the world understood the spiritual powers of the underworld. For millennia, natural caves and caverns were turned into sacred underground temples and, from holy mountains and cliffs, churches were beautifully carved into solid rock.

Offering a guide to the spiritual energies that flourish beneath the surface of the Earth, Jean-Pierre Bayard explores the esoteric mysteries of the underworld, including the symbolic significance of caves, caverns, and underground temples. He examines in depth the myths, symbology, deities, and beliefs connected to the underworld from many different cultures and mystery traditions, from ancient Egypt to Scandinavia and Europe to the Middle East and India. He investigates the role of the underworld in initiatory rites, such as the Orphic Mysteries and Christ's descent into hell, revealing that at the heart of these teachings is the transformative power of a hero's descent into and return from the underworld. The author connects the esoteric attributes of the world below with the cult of the Black Madonna and the earlier cult of Isis. He discusses the telluric currents that run through ley lines, the significance of underground waterways, the esoteric properties of gems and stones, and the "mineral blood" of the alchemists. He also looks at Hollow Earth theory and the denizens of the subterranean realms, such as dragons, gnomes, and dwarfs.

Explaining how the Earth is the womb of the world, Bayard shows how initiatic descent into the sacred subterranean realms reflects the descent of spirit into matter and its slow crystallization. By entering the body of the Earth Mother we are transformed, initiated into primordial wisdom and reborn as spiritual beings.