A multidisciplinarian, de Certeau wrote ground-breaking studies in fields as diverse as mysticism, the act of faith, cultural dynamics in contemporary society, and historiography as an intellectual practice. His impact continues unabated, with new volumes appearing regularly, and perhaps surprisingly his reputation is growing even more rapidly in English and German-speaking countries and the Mediterranean than in his native France. This strong and growing interest in academia is not matched in the public sphere, however, partly due to his being considered a "difficult" author because of his highly personal style which makes translation difficult, and partly due to the declining status of French in the world generally. Nevertheless, portions of his prolific output have been translated into a dozen languages.[27]