Maria Callas, the soprano whose intensely dramatic portrayals made her the most exciting opera singer of her time, died of a heart attack yesterday at her home in Paris. She was 53 years old. Miss Callas had told some friends this summer that she was concerned about her health, but other associates reported that she had been in perfect health and was preparing to write her autobiography for a New York publisher. She once said, "Wherever I am, it is hectic." This may even have been an understatement. Controversy, legend and myth surrounded the soprano throughout the major part of her career. Those who admired her felt that she was one of the greatest opera singers of all time, while others believed that her vocal inadequacies precluded any such claim. Disputes and legal action seemed to arise wherever she sang. Her private life was seldom out of the limelight. Yet there was no denying that it was the magic of her personality that made every move of hers newsworthy. A balanced reaction to Miss Callas's artistry was expressed by Harold C. Schonberg, the music critic of The New York Times, after her return to the Metropolitan Opera in 1965 in the title role of Puccini's "Tosca." "If you want brains, an awesome stage projection, intensity and musicianship, Miss Callas can supply those commodities more than any soprano around," Mr. Schonberg wrote. "But if you look for voice and vocal splendor in your Tosca, Miss Callas is not the one to make you happy." Earlier in the review he had written that "her conception of the role was electrical. Everything at her command was put into striking use. She was a woman in love, a tiger cat, a woman possessed by jealousy. . . . This was supreme acting, unforgettable acting." There is no question that Miss Callas sparked new interest in the largely forgotten bel canto operas of the 19th century. These were the words of Bellini, Donizetti and Rossini, most of which had not been heard since the era when they were written. They were considered too difficult and too uninteresting musically to be worth reviving. Miss Callas showed that they could be sung, that the melodies and all the embellishments that were thought to be for virtuoso display could be turned to genuine dramatic use. It opened up a whole new repertory for singers such as Joan Sutherland and Beverly Sills to follow the path set by Miss Callas. When the soprano was told that she was considered temperamental, her answer was, "I will always be as difficult as necessary to achieve the best." Everyone who worked with her agreed that she was a hard worker, willing to rehearse more than expected, even when a role or a production was not new. Early in her career she sang as many as 16 roles in one season, and she was a quick study. Her own interest in bel canto grew in 1948 in Venice, when she learned the difficult part of Elvira in Bellini's "I Puritani" in five days in order to substitute for an ailing singer. Maria Anna Sofia Cecilia Kalogeropoulos was born Dec. 3, 1923 in Manhattan's Flower and Fifth Avenue Hospitals, her Greek parents had arrived in the United States a few months earlier. Her father was a pharmacist. Years later, in discounting the rumor that she had been born in Brooklyn, Miss Callas said that she remembered living in Upper Manhattan over a drugstore owned by her father. She attended Public School 164 at Wadsworth Avenue and 164th Street in Washington Heights, and by the age of 9 was singing for her schoolmates. The soprano spoke often of her unhappy childhood, which was marred by the squabbles between her parents and her jealousy of her older sister--Maria was squat, while her sister was attractive and favored by the parents. The family returned to Athens when Maria was 13. She won a scholarship to the Royal Academy of Music, where one of her teachers was Elvira de Hidalgo, a famous Spanish soprano in her day. She remembered Maria as being "square and fat, but she put such force, such sentiment, such wonderful interpretation into all she sang. She would want to sing the most difficult coloraturas, scales and trills. Even as a child her willpower was terrific." Before she was 15, the student was singing the dramatic role of Santuzza in Mascagni's "Cavalleria Rusticana." Four years later she made her official debut with the Athens Opera. At the end of World War II, she went back to New York on her own. She auditioned for the Metropolitan Opera at the time that Edward Johnson was the general manager. She was offered the title roles in Puccini's "Madama Butterfly" and Beethoven's "Fidelio." "Fidelio" was to have been sung in English. Miss Callas recalled the impossibility of singing Butterfly: "I was then too fat--210 pounds." As for "Fidelio": "Opera in English is so silly. Nobody takes it seriously." She turned down the offers. She came close to making her American debut in Chicago with a group of Italian singers, but that fell through for financial reasons. In 1947, she was given a contract to appear in Verona, and she sailed for Italy. She made her debut in the famous Arena in the title role of Ponchielli's "La Gioconda." Also making his debut in the opera was the late American tenor, Richard Tucker. In Verona, Miss Callas met one of her most important mentors, the Italian conductor Tullio Serafin. He took her to Venice, where she sang roles that required a dramatic voice, Isolde in the Wagner opera, Turandot in the Puccini opera, even Brunnhilde in Wagner's "Die Walkure." In other cities she sang the name parts in Verdi's "Aida" and Bellini's "Norma." The natural goal of every opera singer in Italy then, as now, was La Scala in Milan. Miss Callas sang an Aida there in 1949, but it was not in the regular season. She would not join the company officially until 1951, because already independent minded. She would sing only leading roles in major operas and would not share a percentage of her salary with a powerful artist agency in Milan. In the early 50's, Miss Callas sang in a number of rarely heard operas in Italian houses. These included Haydn's "Orfeo ed Euridice," Gluck's "Alceste" and Cherubini's "Medea." She had a notable triumph in the last work, which was staged by Luchino Visconti and conducted by Leonard Bernstein. She was offered a contract at the Met in 1952 by the general manager, Rudolf Bing, but this did not work out because she would not come to New York without her husband, Giovanni Battista Meneghini, who was unable to get a visa. In this period, she had gained experience and a large measure of success not only in Italy, but also in South America, Mexico and Covent Garden in London. She took off 70 pounds, which left her at a slim 135 pounds. At 5 feet 8 inches tall and with a face made striking by her broad cheekbones, she became one of the handsomest women of the operatic stage. She finally made her United States debut in 1954, with the Chicago Lyric Opera, in the role of Norma. Two years later, on Oct. 29, she sang the same part for her debut at the Metropolitan Opera. By this time her reputation was such that announcements of her appearances generated long lines outside the box office of the houses where she was to sing. Although critical reaction was usually mixed because of the individual timbre of Miss Callas's voice and the flaws in her technique, she was ecstatically received for her musicianship, her personal appeal and the originality of her characterizations. Miss Callas's voice, which some critics maintained was man-made rather than natural, had three sections. At the top it was inclined to be steely, even shrill, and the highest notes were often little more than shrieks. The middle voice could have a covered sound or could be velvety; used at a soft level, it was beautiful. But in the lowest register it could be edgy again. Technically, the soprano often did thrilling things with the tonal coloration and with the fioriture, and she could sing a descending chromatic scale dazzingly. But sometimes, too, the voice would not respond smoothly to the demands she made on it. Having conquered many of the great opera companies of the world, the soprano began to have trouble with them. In Chicago she was served with a lawsuit backstage during a performance, and she said she would never sing there again. She was accused of breaking a contract with the Vienna State Opera over a question of fees. She canceled an engagement with the San Francisco Opera just before the season opened, pleading illness, and the company preferred charges against her with the American Guild of Musical Artists, the singers' union. At the gala opening of one season in Rome, she sang the opening act of "Norma" and then refused to go on after that, because of laryngitis. At the Met, she quarreled with Mr. Bing over a matter of dates and repertory, and he canceled their contract. She did not show up for scheduled performances at the Edinburgh Festival and at Athens. All these actions made headlines, and Miss Callas earned a reputation for temperamental behavior. She had an answer to these charges, in most cases explaining that she would not sing unless she or performing conditions were at their best, and this was the reason for her walking out on performances or contracts. "To me, the art of music is magnificent, and I cannot bear to see it treated in a shabby way," she said in a Life magazine interview in 1959. "When it is respected and when the artists who serve it are respected, I will work hard and always give my best . . . I do not want to be associated with inferior staging, taste, conducting or singing." In fact, most of the feuds were patched up, and Miss Callas returned to sing with the various companies again. She was considered too valuable an artist and too great a box-office attraction to ignore. As Mr. Bing said of Miss Callas yesterday after he heard of her death: "I was privileged to bring her to the Met and I am proud of that. She was a difficult artist, as many are, but she was one of the greatest artists of her time. We will not see her like again." In fact, Miss Callas, was re-engaged by the Met in 1965 to sing Tosca, and these became her last public opera performances. In subsequent years, the soprano would make announcements from time to time that she was considering singing somewhere, causing a flurry of excitement in the music world. But no performances materialized. In 1971, she went to the Juilliard School to give a series of 12 master classes. These were jammed with auditors, many of them coming from out of New York City, and Miss Callas was credited with exceptional success in her teaching. In 1973, she and her close friend, the tenor Giuseppe di Stefano, tried their hand at staging opera. They directed a production of Verdi's "I Vespri Siciliani" in Turin, but in the view of the critics, the results were disastrous. That same year, they decided to make a worldwide concert tour. It began in Hamburg, West Germany, in October, and the singers appeared at Carnegie Hall in two programs in February 1974. The audience was almost hysterical in its adulation, but the critics lamented that there was not much left of Miss Callas's voice, even if her interpretations remained unexcelled. When the tour ended, it represented the soprano's last singing in public. She did, however, continue to add to her extensive list of recordings. When she married Mr. Meneghini, 20 years her senior, in 1949, the Italian building- materials tycoon gave her security and, it was said at first, affection. She called herself professionally Maria Meneghini Callas, and he became her manager and agent. They were separated in 1959 after she had become romantically involved with Aristotle Onassis, the Greek shipping magnate. The marriage with Mr. Meneghini was annulled six years later. The public eagerly followed the relationship between the singer and the entrepreneur, particularly after it was learned that Mr. Onassis had given her controlling stock in a $3 million freighter. They had apartments near each other in Paris. When Mr. Onassis married Jacqueline Kennedy, attempts were made to have Miss Callas comment on a supposed rebuff. The singer said little about it except that she and Mr. Onassis were still good friends. The singer was also known for the bitterness with which she spoke of her family. "There is no communication between my family and me," she said in 1971. "I know my mother wrote a book about me, but I never read it." She also broke with her musical mentor, Mr. Serafin, ostensibly because the conductor chose another soprano for a recording that she had expected to make with him. A celebrated feud between Miss Callas and Renata Tebaldi, who was her contemporary, was kept alive in the press and by the fans of the respective sopranos. They were rival singers at La Scala at one time, and it was reported that they avoided each other backstage. Miss Tebaldi refused to attend Miss Callas's performances, while Miss Callas went, with some ostentation, to those of the other soprano. Gossip writers hinted that she did so in order to make Miss Tebaldi nervous. In 1968, Miss Callas attended the Met's opening performance, in which Miss Tebaldi was singing the title role of Cilea's "Adriana Lecouvreur." Afterward, the two singers met backstage and this time embraced each other. In recent years, Miss Callas's name had been steadily linked with that of Mr. di Stefano. They had frequently sung on stage and in recordings together in the earlier stages of their careers. Miss Callas made a film based on Euripides' "Medea," which was released here in 1971. It was written and directed by the late Pier Paolo Pasolini. Leonard Bernstein, the conductor, on being informed of Miss Callas's death, said yesterday, "Besides being a cherished friend, she was for me the uniquely great singer of bel canto in the mid-20th century and has for some years been irreplaceable." Dario Soria, former head of Angel Records, the label on which Miss Callas's recordings have been issued in this country, and now director of the Metropolitan Opera Guild, had remained a steadfast friend. He said yesterday that he had talked by phone to the singer last summer, and that she sounded remote in spirit. In response to a query as to what she was doing, she told him in a flat voice, "Nothing." "Without being able to perform," Mr. Soria said, "she apparently had nothing left to live for." Mr. Soria also summed up Miss Callas's career succinctly: "As a singer she was responsible for the revival of bel canto. As an actress, she made the stage exciting theater. As a personality, she had the kind of magic that makes news. I think she'll be remembered as one of the greatest opera singers of all times." Soprano Led Bel Canto RevivalBy HAROLD C. SCHONBERG More than any singer of the period following World War II, Maria Callas dominated opera, even changing the course of the repertory. It was because of her that the revival of 19th century bel canto operas started: and in a way, such famous singers as Joan Sutherland, Beverly Sills, Teresa Berganza and Marilyn Horne are her children. Miss Callas took a completely neglected repertory, the operas of Bellini and Donizetti, and by the magnetism of her voice and dramatic ability showed they were still viable. A whole generation of singers followed her lead. Of course she sang other things. She was famous as a Verdi and Puccini singer, and she included in her repertory such seldom-heard operas as Cherubini's "Medea" and Gluck's "Alceste." She was a prima donna assoluta in the old tradition. By virtue of voice, musicianship, a magnetic stage presence and a flaming temperament, she was in the news wherever she went and whatever she did. She moved in the ranks of the highest international society, she had liaisons with billionaires, and she was glamour incarnate. No singer of her time, and very few in history, could so dominate an audience. The last time she sang in Carnegie Hall, in a recital with Giuseppe di Stefano, a voice bellowed from the balcony when she made her appearance: "You are opera!" She may, toward the end of her career, have had vocal difficulties, but that made no difference to her hysterical admirers. To them she was the one singer who represented opera as theater--the artist who lived her roles and made them come to life. Tall, slim, commanding, exotically beautiful, Miss Callas had a unique combination of electricity and brains. Her voice was in some respects a flawed instrument, undependable in the high register. In the middle range it had a haunting beauty. Her imposing bottom register had a different quality entirely and it was said of her, not always admiringly, that she had three voices. By virtue of sheer determination, she triumphed over her vocal limitations. She immersed herself in her roles, studying every word and every phrase for maximum musical and dramatic effect. Her singing was full of subtle inflections, accentuations, shadings, that were foreign territory to most other sopranos. She extended this kind of superior musicianship to her approach to the stage. Every gesture meant something, every movement and facial expression was aimed toward an emotional or dramatic climax. Thus in the bel canto operas, which sopranos of the past sang with the limpid innocence of a canary, Miss Callas was able to find hitherto unrealized depth and power. In the large-scale operas, such as "Aida," "Norma" or "La Gioconda," she sang with such focus of concentration that it could be almost a terrifying experience. Even when her voice was not under control, the intensity of her conception made one forget her struggles with pitch and high notes. This burning sense of theater, this powerful musicianship, was hers alone. As careers go, hers was not long. She made her debut in 1947, and was virtually sung out 20 years later. But during those 20 years she exerted an influence on opera that was unique. She looked on opera as theater as well as voice, and she was the one who put it all together.