Michel Herr had met the German saxophone player Wolfgang Engstfeld when he played with the German band Jazztrack in the early seventies. A few years later, in 1978, he and Bruno Castellucci called Wolfgang to record the quartet album Perspective. Michel Herr (piano), Dutch bassist Wim Essed, Wolfgang Engstfeld (tenor sax) and Bruno Castellucci (drums). Here live in Beauraing (B), circa 1978.