In the face of great challenges, utopian thinking is currently in vogue. The fact that utopias, with their ideas of an idealized target society, are not compatible with the basic features of an Open Society was already pointed out by Karl Popper in his book 'Die Offene Gesellschaft und ihre Feinde' (The Open Society and its Enemies) under the impression of National Socialism and Stalinism. In the present book, further forms of Closed Societies and...