She strikes you as a person, a woman, whose whole extraordinary personality flows out into opera. As if this were not enough, everything transmutes into the work at hand, into gesture and song. This is as true of the way she looks at a confidante or starts when she hears of a calamity or lays her hand on somebody's arm, as it is of her portamento and her legato. Opera depends on the happy fiction that feeling can be sustained over impossibly long stretches of time. Callas is one singer who is emotionally equal to the job.
Every note falls unerringly and beautifully into place.
She's just all there, and it seems as though the composer himself were singing. So she avoids loud singing as much as she decently can, and makes stunning use of mezza voce in the high register. Callas controls and manipulates her voice as perfectly as Elisabeth Schwarzkopf or any other great technician. Yet in a way nothing could be more impressive than her transformation of this role.