espite an effective career which did not even last 18 years, Maria Callas will probably go down in history as the most important singer of the second half of the 20th century. What made her unique in her time was her attention to verbal nuance and matching gesture. Yes, there were singers who trod that path a few decades earlier, but plentiful aural and visual documentation is lacking for Lotte Lehmann, Claudia Muzio or Rosa Ponselle, to name just a few. And while we can hear Callas in almost all her roles and at various stages in her career, the plentiful photos unfortunately do not compensate for the skimpy live visual coverage. Callas is an artist who needed the stage to come to life; even if she brought fascinating moments to almost all of her studio incarnations, listening to some of the "unofficial" versions allows us to appreciate the artist at her full worth. It is worth considering what made Callas so special at a time when Renata Tebaldi and Zinka Milanov were in full triumph at the Metropolitan Opera. Both Tebaldi and Milanov possessed a lushness of voice which was never a Callas attribute, but neither of them had a coloratura technique that enabled them to tackle Bellini or Donizetti (despite Milanov's attempts at Norma) or had the knack of uttering a line unforgettably, as the often-cited ma in Una voce poco fa or much of Tosca or La Traviata.

1. Bellini: Norma
With two official EMI versions and five complete live recordings, Norma is at the top of the Callas hit parade, but choosing a single version is a nightmare as each has its virtues, based on the state of the soprano's voice or the surrounding cast. On balance, our choice lies with the first studio recording where the balance between vocal health and emotive quality is as good as one can get for this artist. Cast includes Ebe Stignani, Mario Filippeschi and Nicola Rossi-Lemeni, conducted by the venerable Tullio Serafin.
EMI 5 56271 2 (3 cds) - recorded in 1954

2. Bizet: Carmen
A recording which may not be one's first choice for a performance of Carmen, but it is Callas at her best: the range is comfortable for her in 1964, the rest of the cast is French to the core and Callas lives the role, as her last act makes clear, without ever having sung it onstage. Cast includes Nicolai Gedda, Andréa Guiot and Robert Massard, conducted by Georges Prêtre.
EMI 5 56281 2 (2 cds) - recorded in 1964

3. Cherubini: Medea
One of the first things we must accept today in listening to the Callas resuscitations is the lack of philologic concern in the interests of presenting a drama. Medea suffers the most, with its use of the Lachner recitatives, but what Callas does with them is extraordinary. Here we must turn to one of the pirate versions, but the choice is not easy: either the Scala premiere conducted by Leonard Bernstein, or the Dallas performance with Teresa Berganza and Jon Vickers or Covent Garden with Fiorenza and Vickers, both of the latter conducted by Nicola Rescigno. Ultimately, it is the Dallas that wins the day for the slightly less monolithic version chosen by Rescigno so that Medea regains some of her humanity.
Melodran 26016 (2 cds) - recorded 6 November 1958