The cases presented in the brochure are so fantastic that no less fantastic and bold hypotheses are required to explain them. We are talking about the so-called poltergeist - incomprehensible phenomena accompanied by the spontaneous movement of objects, voices and knocking coming from nowhere, spontaneous combustion, etc. This issue of “Question Mark” tells about what is known about poltergeists today, the most common and interesting hypotheses. .The book’s text has been translated from the original language using an artificial intelligence system. In most cases, the translation is accurate and clear, but occasionally there may be incorrect phrasing or individual words left untranslated.