LUXEMBOURG.- “The essence of all photography is documentary in nature”, observed August Sander in one of the talks that he delivered at the Westdeutscher Rundfunk (West German Broadcasting Institution) in Cologne in 1931. With this he coined a key phrase, which was to shape his view on photography throughout his career. August Sander gained fame with a photographic work created during the mid-1920s, entitled Menschen des 20. Jahrhunderts (People of the 20th Century), in which he brought together portraits of people from different social backgrounds and occupational categories as part of a self-conceived project that spanned decades. A hundred images from this work were first exhibited in 1927 in an exhibition at the Cologne Kunstverein and