Mountain spirits, water spirits, goblins, brownies... The idea of some invisible entities living next to us has always been present in the human mind. Sometimes these entities are far from us and live without causing any trouble, but it also happens differently: such an entity inhabits a person and causes a lot of inconvenience, and sometimes even trouble. So who are they? Tenacious fairy-tale heroes or real creatures, just built differently from us? What does this neighborhood threaten us with? Can a person somehow influence them? An attempt to understand these issues has been made in this publication. The text of the book was translated from the original language using an artificial intelligence program. For the most part, the translation of the text is of very high quality, but in some cases, due to the imperfection of the technology, there may be incorrect phrase translations in the text, as well as single words and expressions may not be translated.