The first collection under review covers the second half of Dame Joan Sutherland’s recording career and also straddles the change from analogue to digital recording. That affects the sound: early Decca digital recordings (in the early-mid 1980s) tended to have a sharp glare in the treble and little if any warmth, affecting the voices and orchestras (notably violin sections). On the other hand, sound is very clean and clear.

Arguably, Sutherland hit her prime earlier than this. By the time of the first recording here, Verdi’s Rigoletto (1971), she had adopted the swooping phrasing and covered consonants that many people criticised. By 1982, when the recording of Bellini’s La Somnambula was made, she was addressing these matters to some extent, but by 1988 when Cilea’s Adriana Lecouvreur was recorded her vibrato has widened, and her lower and mid-range sounded thin and wobbly. Her extraordinarily strong and flexible top range never suffered. Those purchasing this set should be aware that the great soprano was in fresher voice in her earlier recordings of Rigoletto, La Traviata, Bellini’s Norma and Donizetti’s Lucia de Lammermoor (available in the preceding collection).

Generally, the supporting singers were weaker in the earlier versions, with the notable exception of...