[In memory of the life and work of Helmut Rennert (1920-1994)].

To mark the 90th anniversary of the birth of Helmut Rennert (1920-1994) in 2010 an overview of his biography and scientific work will be given to highlight his important contribution to the classification of psychoses. He rose to prominence above all with his model of the universal genesis of endogenous psychosis in which Rennert advocated the idea of unitary psychosis. The lively discussion regarding nosological, categorical, syndromatological and dimensional approaches for the further development of classification systems of mental disorders illustrates the prevailing relevance of his ideas. For the first time it was possible to access the archival sources in the German Academy of Sciences Leopoldina and the University of Halle (Saale) for this purpose. In addition, the personal experiences of former staff members and representatives in the field of psychiatry assisted in compiling a comprehensive picture of Rennert as a teacher and colleague who contributed a great deal to the development of psychiatry in East Germany.