Mannheim's book "Ideologie und Utopie" (1929) was the most widely debated book by a living sociologist in Germany during the Weimar Republic; the English version "Ideology and Utopia" (1936) has been a standard in American-style international academic sociology, carried by the interest it aroused in the U.S.A. The German and English versions of the book are quite different. This has led to reappraisals of Mannheim started by new texual discoveries and republications. Mannheim's sociological theorizing has been the subject of many book-length studies, evidence of an international interest in his principal themes. Mannheim was not an author of any work he himself considered a finished book, but rather of some fifty major essays and treatises. Most of these were later published in book form.