Claims of supernatural realms, parallel worlds, and lost civilizations are put to the test in this well-researched guide to the unexplained. Firsthand accounts and historical documents are explored, and in-depth coverage is provided on the mysteries of imagination, culture, perception, consciousness, being, and more. Included in this collection are Richard S. Shaver's personal experience of hell—replete with demons and ghouls—modern and ancient accounts of fairyland, life on Mars, alien worlds, parallel universes, and mystery airships.