Gustav Landauers letters are part of the remarkable correspondences of the late 19th century. For the first time they were collected by his friend Martin Buber and published in two volumes "Lebensgang in Briefen" in 1929. After 1945 they became high treasured testimonies of the lost german-jewish culture, which was involved in oppositional circles of the German Kaiserreich as well as in the aesthetic and philosophical modernity. In Landauers correspondences the writing of letters, which was in former times a prominent kind of bourgeois art of conversation, has become a pragmatic medium to preserve life as well as it can be seen as an elaborated work equipment, used by the interpreter, the journalist, the dramatic adviser and political philosopher. Landauers letters are addressed to Wilhelm Bölsche, Else Lasker-Schüler, Martin Buber, Erich Mühsam, Fritz Mauthner, Hugo von Hofmannsthal, Petr Kropotkin.