editor journalist publisher translator writer
Together with Werner Fuchs and Ulrich Kiesow he founded Fantasy Productions, which became one of the premier German RPGand board game producers and retailers. As an editor he co-founded the highly successful German-language role-playing game The Dark Eye and the Science Fiction Times and as a critic he was a contributor to Science Fiction Studies. As a writer he used several pseudonyms including Jürgen Andreas, Thorn Forrester, Daniel Herbst, Gregory Kern, Mischa Morrison, P.T. Vieton, and Jörn de Vries.
He also co-wrote a six-volume series of young-adult San Francisco with Ronald M. Hahn Das Raumschiff der Kinder (translates as "The Children"s Spaceship").
He edited anthologies, annual publications, and reference works. Anthologies included Science Fiction aus Deutschland: 24 Stories von 20 Autoren (1974).
Annual publications included the Science-fiction-Almanach (1981–1987) and Science-fiction-Jahrbuch (1983–1987). Reference works included Reclams Science-fiction-Führer (1982), Lexikon der Science-fiction-Literatur (1980, 1988), Lexikon der Horrorliteratur (1999), and Lexikon der Fantasy-Literatur (2005).
He lived in Hamburg. In 2012 he was awarded a posthumous special Kurd-Laßwitz-Preis for his many years of contributing to German-language San Francisco.