The Westerners whose experiences are in this book made ascensions to what many scholars of shamanism call the Upper World and descents to the Lower World, as contrasted with the one in which we live, which is the Middle World. The worlds above and below are entirely in nonordinary reality, and they are solely spirit realms, while the one we live in has both its ordinary-reality aspect, the one we easily perceive, and its nonordinary aspect, which is a domain of spirits and is less easily perceived without shamanic training. The Upper World is quite different from the ordinary-reality phenomena above us, the phenomena observed by astronomers. Even the most distant galaxies of our universe are still not the Upper World of the shamans. The Westerners, in descending to the Lower World, were likewise not going down the rock layers of the geologists’ Earth but were passing into a purely spirit realm below us, one without earthly limitations. This book provides examples of nonordinary Western experiences in all three worlds, with the main emphasis being on the Upper World, partially because today in the West there seems to be great curiosity about what, if anything, is “up there” spiritually. In other words, are heavens real, fantasy, or metaphorical? Our evidence suggests that the answer depends upon which of two realities, ordinary or nonordinary, one is talking about. In nonordinary reality—accessed with classic shamanic techniques, including auditory driving—there now seems to be no question of the existence of heavens, celestial choirs, deities, and the presence of beings, or spirits, in the Upper World. Evidence is also presented for the existence of spirits in our own world, the Middle World. The ascension-derived evidence in this book challenges the beliefs of those who claim that there is only one heaven and that round-trips there are restricted to a few long-dead prophets, saints, and founders of Great Religions. Evenhandedly, the reports also challenge the beliefs of those atheists and “secular fundamentalists” who think that heavens are figments of the imagination. Even in Christianity today, some members of the clergy suggest that heaven is a feeling rather than a place. Years ago in The Way of the Shaman I gave Westerners an introduction to making shamanic journeys to the Lower World, and many have traveled there during the past three decades. That is one of the reasons I do not place as much emphasis in the present book on the Lower World as on the Upper. Still, the final chapter of Cave and Cosmos provides new and surprising information about what some Westerners have discovered in the Lower World.