Richard M. Bucke's astonishing treatise on the human mind discusses and attempts to explain mystical experiences in the context of evolutionary change in the brain.

During his mid-thirties, Bucke underwent a feeling of intense revelation and felt distinctly enlightened for a short time. Although the period of enlightenment passed, it had an immense impact upon Bucke's outlook, steering his personal and professional life in a directions he had never before envisioned. He found th