 In the 1950s he began to tour in Europe again as a recitalist.He became a member of the faculty at the "Internationale Ferienkurse für Neue Musik" in Darmstadt, Germany, along with his close friends and long-time associates Eduard Steuermann and Theodor Adorno.Except for one year (1956) spent in Darmstadt, he remained active in Madison until reaching the mandatory retirement age in 1966.