Visconti’s sensational 1955 production of La sonnambula for La Scala, Milan, was revived and recorded two years later. As a girl, Callas had fallen in love with the rôle of Amina; as an adult it suited her voice perfectly, and her interpretation set a benchmark that few have equalled. Among the many highlights of Callas’s profoundly satisfying performance is her cadenza for Ah non giunge in which she executes a remarkable diminuendo on a stratospheric E-flat, a feat unrivalled in the history of the gramophone.This is by any standards a classic recording.