The tracks on this album were recorded over a period of no less than 16 years. The earliest, the two versions of Donna Anna’s Non mi dir, date from 1953, and were intended to test microphone placings before Callas made her first commercial recording for EMI - Lucia di Lammermoor.

The latest, the Verdi arias recorded with Nicola Rescigno in 1964–1965 and 1969, were never approved for release by the soprano. When Callas Rarities was first released in 1993, Gramophone wrote: ‘Each item, each phrase almost, has something to be said about it: the whole collection makes essential listening.’