'IN THIS palace, thousands of years ago, a desperate cry rang out, and that cry took shelter in my heart.'' Principessa Lo-u Ling is singing in high A, moving to a heart-rending citrus-sharp C. Though she is from the long-gone past, such is the strength of her voice she is inside us. Maria Callas, too, is from the past, but she also is with us. Fifty years since she offered us her Turandot, 25 years since her death, today the siren will engage our attention once more, courtesy of a Radio 3 special.

But fear not, leave go that

mast, we shall not be drowned. Though so stunningly beautiful Cyclops himself would have winked, Callas's visage was not her real strength.

Until I heard Callas sing I'd always believed opera singers were big-haired, big-chested show-offs, belting out a cross between Kelvinside patois and Masai war dirge. Callas, however, changed my mind. The epitome of an operatic soprano, she remains the point of reference for all who have followed. Her range was incredible: from canon-heavy Wagnerian to feather-light coloratura. Her tone was not always steady, at times almost suffocated by emotion, but all the more interesting for this, and that dusk-laden timbre was shades beyond the pale.

How can I put Callas's voice on to the page? Well, sometimes it's like this: ''!!!!!!'' , incredibly loud, almost out of control, grabbing you by the bonce and shaking you until your vitals are jelly. And sometimes, like this: . . . yes, that subtle. The diva herself once noted: ''When music fails to agree to the ear, to soothe the ear and the heart and the senses, then it has missed the point.'' She sought to ensure her audience never missed the point.

Her own life, of course, was never mundane. She was born of Greek parents in New York on December 2, 1923, but when they separated in 1937 she went with mama to Greece. Aged 14, with the build of a Tonka truck,

clumsy on her two left feet, she was, nevertheless, a naturally

gifted singer, and this talent was refined by Elvira de Hidalgo at the Athens Conservatoire.

Shedding almost five stones, Callas reinvented her entire persona long before Oprah taught us that we should learn to love ourselves. She began singing professionally in 1941 with the Lyric Theatre Company in Athens, before returning to New York with big ambitions. She secured La Gioconda at the Verona Arena in 1947 and there followed invitations to perform super-heavyweight parts such as Turandot, Aida, and Isolde.

She next moved into the bel canto repertoire to Rossini, Donizeni, and Bellini, where her dramatic talent breathed new life into a neglected area.

Her greatest triumphs were won in Norma and Lucia di Lammermoor, and throughout the 1950s she was acclaimed in all the major houses, no more so than La Scala in Milan, where she made her debut in Aida in 1950.

During the 1960s, she gradually withdrew from the stage - her last appearance was as Tosca at Convent Garden in 1965 - but continued to record for EMI.

Offstage, her life was as dramatic as any of her characters. The press documented every little excess. And Callas had her moments: in Vienna she sent a private plane to collect a painting left behind in her bedroom. Unless the tiny eighteenth-century oil of the Holy Family was hung in the dressing room, she simply refused to play.

But of special interest to the world was her relationship with Greek shipping magnate Aristotle Onassis. As has been turgidly documented in Greek Fire, the tawdry yet compelling account of the affair by Nicholas Gage, Callas and Onassis became lovers during a three-week Mediterranean cruise in 1959, a nautical but nice sojourn where respective spouses were present and esteemed guests included Winston Churchill and his missus. Callas was 33,

Onassis 53, yet the bond was immediate. Perhaps Callas was disillusioned by her inability to further her career. Maybe it was their shared Greek heritage.

To be sure, she couldn't have fallen for Onassis on his looks - despite the fact that, as one friend put it, ''he looked a lot taller when he stood on his money''.

But Onassis knew how to make an impression: one valentine card was made of solid gold, studded with diamonds and emeralds, and wrapped in a mink coat.

Whatever the reasons for her attraction to the wrinkly Lothario, for Onassis she gave up both career and husband, Gian Battista Meneghini, the ''old man'' who had helped to nurture and develop her early career.

She was rather put out, then, when Oily Onassis chose instead to cop off with Jacqueline Kennedy. He had forgone the unconditional affections of his angel for the kudos of marrying the world' s most famous woman.

With the death of her love, so her interest in life waned. She

retreated into her own private universe, becoming a recluse in Paris, listening to her own recordings. Bruna, her maid, reported: ''La signora didn't sleep at night, she listened to her own voice. I tried to take the records away from her, but she wouldn't let me.''

Callas's heart had been broken. It finally let go one morning in 1977. She was 53.

Our fascination with the diva shows no diminishing, however. When Callas's underwear was auctioned in Paris two years ago, the lot was bought on behalf of the Greek government and subsequently burned ''to save the dignity and honour'' of their heroine. Robert Sutherland, the last pianist to play for her, commented: ''It is all right to sell her dresses, but

her underwear? Selling that is

very tasteless.''

Thankfully, tonight Radio 3 will be selling Ms Callas very tastefully indeed. First off, Stelios Galatopolous (he's from Greece, too, don't you know) explores some of the melodramas of Callas's life, while Rodney Miles comments on her gallery of tragic stage heroines. Interspersing this are excerpts from Bellini's Norma and I Puritani - the opera in which, guided by veteran conductor Tullio Serafin, she startled the music world by singing the coloruta role of Elvira.

There is also the chance to

hear some of the masterclasses given at the Julliard School of Music in 1971.

Next up is Liebestod from Tristan and lsolde, sung in Italian, and then a rather Channel 5 monickered Greece: The Early Years, wherein Tony Palmer explores Callas's time spent studying in Athens. There are also contributions from fellow pupils.

A bonus to those such as I who know nothing about the mechanics of singing, vocal coach Gerald Moore analyses Callas's own special vocal techniques.

Baton down the hatches,

buckle up, and hold tight as, with the nine o' clock watershed we launch into the mad scene form Lucia di Lammermoor.

Finally, as we near the witching hour, the grand finale is the end of act two from Tosca. I dare all hair follicles not to stand to attention.

So unplug the television, the phone, the internet, and recall the personal satellite. Tune in, close your eyes, open your ears, fill your heart. When Callas sings it reminds us that, despite everything, we humans can aspire to and reach ethereal heights, that we are capable of incredible beauty.

Truth be told, Maria Callas died too full of pills and too empty of friendship. The heart of the greatest singing artist we have never known gave out, alone, in her Paris apartment. Do we love her? Dare we say love? Well, why not? Callas knew: she told us so in Madame Butterfly: ''Maybe, because we are afraid to say the word for fear of dying from it.''

CAllas: the top fives

The top five quotes:

When my enemies stop hissing, I shall know I'm slipping.

I would like to be Maria, but there is Las Callas who demands that I carry myself with her dignity.

I cannot switch my voice. My voice is not like an elevator going up and down.

You must serve music. You must take this voice and break it up into a thousand pieces, so she will serve you.

First I lost weight, then I lost my voice, and now I've lost Onassis.

The top five performances:

Bellini: Norma

Norma tops most opera lovers' hit parades. Go for EMI's first studio recording where the cast includes Ebe Stignani, Mario Filippeschi, and Nicola


Bizet: Carmen

Callas at her best, proving her supremacy throughout the vocal range.

Donizetti: Lucia di Lammermoor

Callas revisited the role of Mad Lucy often, and the sheer drama shines through. Get the performance recorded for EMI in Berlin, on September 29, 1955, with the Berlin Radio Symphony Orchestra.

Puccini: Tosca

Tosca will be forever

associated with Callas. Her debut with Giuseppe di Stefano and Tito Gobbi and Victor de Sabata is for some critics the greatest opera recording ever made.

Verdi: La Traviata

The most popular and complete recording of Verdi's masterpiece is the 1958 recital in London's Covent Garden with Cesare Valletti and Mario Zanasi, conducted by Nicola Rescigno.