Historians constitute a rather conservative breed, and of course some historians are more conservative than others. The comfort zone of a conservative historian is a document, that is a preserved text, especially one that has some kind of official provenance. Memoirs, testimonies, oral history — the conservative historian considers them at best to be second-rank sources, too subjective and uncertain. This kind of historian does not even recognize visual materials as sources and makes no use of them. But this is unfortunate, because we live at a time in which all sorts of information is presented ever more frequently by visual means. Our students have become accustomed to acquire information in a form...