German composer of mostly chamber, choral, piano, and organ works that have been performed throughout Europe and elsewhere.

Mr. Stiebler studied composition and piano at the Hochschule für Musik und Theater Hamburg, but had more important lessons at the Ferienkurse in Darmstadt from 1958–61, including studies with Karlheinz Stockhausen in 1959.

Among his honours are the Bach-Preis der Freien und Hansestadt Hamburg (1966) and a prize from the seminar of the Künstlerhaus Boswil (1991). Moreover, two of his productions for Hessischer Rundfunk received the Prix Italia (Piece for Peace by Alvin Curran and Die Blinden by Walter Zimmermann).

He is also active in other positions. He served as director of new music for Hessischer Rundfunk from 1969–95 and founded the concert series Forum Neue Musik there in 1989. He co-produced numerous CDs for Hessischer Rundfunk in collaboration with the label Hat Hut, including the series devoted to the New York School. In addition, he has written numerous essays for Musik-Konzepte, MusikTexte and other music journals, as well as booklet notes for the recording of Words and Music by Morton Feldman on Montaigne Auvidis.