Dieter was a Swiss bookseller, publisher, literary agent and author. He was founder of Sphinx Verlag (publishers), now at Verlagsgruppen Random House.
Timothy Leary lived with Dieter while seeking asylum in Switzerland in 1971; Dieter wrote Swiss President Kurt Furgler on his behalf. As Sphinx publishing Dieter represented the works of Alan Watts, Marilyn Ferguson, Joseph Campbell, Frijof Capra, John C. Lilly, Timothy Leary and Aleister Crowley. He founded the Necronomicon with Oscar winner HR Geiger, with whom he had a long friendship.
Dieter established the non-profit Gaia Media Foundation, and the GoodNews Letter. Gaia Media Foundation organized a 100th birthday celebration for LSD discoverer Albert Hofmann at Basel's Natural History Museum, and the symposia and readings of Albert''s book "LSD - Problem Child and Wonder Drug."
Dieter then organized the World Psychedelic Forum (WPF) at the Congress Center Basel, with 2000 visitors from 47 countries.
Dieter wrote (with Lucius Werthmuller) the highly-acclaimed and seminal biography of Albert Hofmann and the history of LSD.
Notably, one of Dieter's last efforts was the careful editing of "The Rose of Paracelsus - On Secrets and Sacraments." The October, 2016 revision is issued in memory of Dieter Hagenbach.
See Dieter's obituary and honorarium in Neue Zurcher Zeitung am Sonntag (August 28, 2016, in German)