Despite reworking and rewriting 'Secular Religion' for about ten years Hans Kelsen finally withdrew the text from printing in 1964. After long and careful consideration the Hans Kelsen-Institut has now decided to lift the veil on Kelsen's somewhat mysterious last book and to bring 'Secular Religion' to a wider public. In this book Kelsen vehemently opposes any attempt to discredit modern science as failed religion, a view prominently held by Kelsen's former student Eric Voegelin. Any contemporary trend towards a 'new' de-secularization will have to face Kelsen's criticism. Furthermore, as Kelsen convincingly demonstrates, any trend towards a 'new' theologization holds the danger of totalitarianism. In this context Kelsen's text from 1964 offers an excellent contribution to a current discussion.