The work is being published for the first time; before that, it had been in manuscript for a long time. The questions raised in it continue to excite the reader, especially in our time. The author, being a physicist, substantiates the reality of the other world, not only from the standpoint of the subjective experiences of eyewitnesses, but also from a physical point of view. Giving examples of the material manifestation of the other world, he examines the conditions under which transitions to other worlds become possible and gives stories about how our ancestors could travel in their bodies through parallel spaces. Some episodes may raise doubts in the reader, especially regarding the issue of the origin of people not from a monkey, but from an extinct anthropomorphic class, which legends of different nations simply call gods. These questions are most fully presented in the series “In Search of the Hidden” in the author’s two main works, “The Russian-Borean Pantheon” and “When People Were Gods.”