As the author of over 150 books, pamphlets, and essays, Hall was a major voice in mystic and metaphysical circles. He rose to prominence in 1928 with the release of his most famous work, The Secret Teachings of All Ages. While continuing to write and give extensive lectures in California, Hall also founded the Philosophical Research Society in Los Angeles in 1934. The center is still in operation today, providing guidance and wisdom to those who seek it.

One of Hall's early works is The Occult Anatomy of Man, in which Hall interprets the human body as the allegorical answer to the mysteries of the universe.

Hall begins by reminding us that the holy writings of most "enlightened people" include some version of the concept that God made man in His own image. From this beginning, The Occult Anatomy of Man explores the idea that as a microcosm of the infinite, the human body contains the answers to the secrets of the universe. Hall states, "[The priests of the ancient world] believed that every star in the heavens, every element in the earth, and every function in Nature was represented by a corresponding center, pole or activity within the human body."

Unsurprisingly, Hall takes issue with literalists and historians and their interpretations of sacred texts. "Those who understand [the Bible's] literal meaning understand the least of its meaning." To illustrate, he describes some of the symbolism in the Bible and lays out their paganistic roots:

"The Christian cross comes from Egypt and India; the triple mitre from the faith of the Mithraics; the shepherd's crook from the Hermetic Mysteries and Greece; the Immaculate Conception from India..."

In our inability to comprehend the vastness of the universe, the great spiritual leaders instead turned inward, looking to that which we could understand to explain that which we cannot. By viewing man as a microcosm of the great cosmos, we can better comprehend the unknowable.

The universe is divided into three parts in nearly all spiritual belief systems - heaven, earth, and a hell or underworld. The heavens are on high, where God resides and looks down upon us. When we pray, we raise our eyes and hands toward heaven. Earth is the middle ground, suspended and connected to both heaven and hell. And hell lies below.

The human body, Hall argues, follows the same pattern. The "skull with its divine contents" is the heaven of the physical form. The spinal column with its 33 vertebrae is the earth, connecting the heavens to what lies below. Jesus Christ, God's son sent to earth for 33 years, is not coincidental. Some ancients referred to the spine as the stairway, or a winding road leading where? To the skull - to heaven. And below are the reproductive organs representing hell or the underworld, the source of our emotional and sexual impulses. This is the furthest from the brain and from our divinity.

Through extensive study of world religions and cultural traditions from both East and West, Hall explains the wisdom of the ancients in this short book. For those curious about man's connection to nature and to the wider universe, The Occult Anatomy of Man is a foundational work.