What is the difference between the scientific revolution and the use of science for unusual purposes? What is the reason for the current revival of anti-science, including pseudo-historical mysticism? Where is the line, crossing which, the historian turns into an extremist ideologist - of his own free will or against it, by the "power of things" alone? And how can the reader determine for himself whether the author he is reading has crossed this line? Here are the questions this book aims to answer. Designed for historians, sociologists, specialists in ideology and modern mythology, as well as for wide circles of readers.