CHRISTINA ONASSIS HAS HAD more luxury in her life than most princesses, even most queens, ever imagine, let alone experience.

The first house she lived in was one of the most celebrated in Europe: the Chateau de la Croe, on 25 magnificent acres in the south of France at Cap d'Antibes between Nice and Cannes. It had formerly been the home and summer palace of such renowned royalty as King Leopold of Belgium, King Umberto of Italy and the Duke and Duchess of Windsor. Christina was only a baby when her father, Aristotle Onassis, then 45, and her 21-year-old mother, Tina Livanos Onassis, moved there in the spring of 1951.

As soon as they occupied the mansion, Onassis hired an extensive staff and a "manager" to take charge of his household affairs, feeling that his wife Tina was too young and inexperienced to cope successfully with the responsibilities of so large and grand a mansion. Onassis wanted Tina to spend as much time as possible with Christina and her older brother Alexander.

Onassis himself, constantly jetting around the world in his multinational business negotiations, was rarely at home and when he was, he had little interest in his young children. Although Tina loved them, she often traveled with her husband: whale hunting in the Antarctic; launching a new freighter in Germany; skiing at St. Moritz; partying in Paris. The two youngsters were usually left at home under the care of the two dozen servants who worked at the chateua.

Christina was given everything she wanted, and was spoiled and pampered by all of the help. The chateau had acres of grounds to romp across, huge stretches of manicured lawns upon which parties were held for Christina and her friends, with enough magicians, clowns, toys and games to fill a circus.

There was an Olympic-sized swimming pool, numerous fountains and gardens, and the property ran directly down to the sea for playing on the beach and in the surf. Christina and Alexander had a variety of pets - a great dane, two French poodles, a horse, a goose and two gazelles (which were a gift from King Saud of Saudi Arabia, a controversial business associate of her father's).

Whenever Tina and Onassis were in residence at the chateau, Christina was allowed, during the early evenings, to attend some of the parties and festivities that her parents constantly hosted. Their guest lists included celebrated people from the worlds of business, royalty and entertainment. J. Paul Getty, Cary Grant, Lily Pons, Claudette Colbert, Merle Oberon, Gene Tierney and Prince Rainier were among those who frequently attended, and Christina would speak with them in French or English.

Oddly, she was never formally taught Greek and could only manage a few words of her father's language. (Her mother had been educated mostly in London, and she and Onassis tended to converse in English or in French).

As Christina grew older, there were other fabled homes, other luxuries: a penthouse on the fashionable Avenue Foch in Paris; a ranch in Montevideo, Uruguay; a townhouse on Sutton Place in Manhattan; a villa on the outskirts of Athens; her father's own private island, the storybook Skorpios, in the middle of the Ionian Sea. Ultimately, Christina would spend most of her time on the world's most palatial yacht, the Christina, a floating Xanadu named in her honor by Onassis.

Life aboard the sleek, white Christina was so opulent and glamorous that it seems more a tale of fiction than fact. Christina's playroom had murals of Parisian fantasy scenes, painted by Bemelmans. There were tiny electric automobiles for her and her brother to ride in around the spotless decks, hobby horses and a tiny electric organ to play with. But except for her brother, there was little opportunity to play with other children aboard ship, so Christina grew up very much in adult society.

Christina attended a round of exclusive schools: Miss Hewitt's classes in Manhattan; private boarding schools in Paris and London.

In the latter, Christina was often the only student who didn't actually live at the school; instead, she was driven there and picked up every day by a chauffeured limousine. This unusual situation kept her apart from her schoolmates, increasing a certain loneliness and aloofness that pervaded her personality. She was not a popular student and had few friends.

Her real learning came from the traveling she was exposed to, and from the influence of her father and his friends. Sitting on the sidelines, Christina would remain silent and totally alert, listening to the conversations around her. Her father spent hours at a time talking politics and philosophy with Churchill. Sometimes Richard Burton held forth on Shakespeare, or Gianni Agnelli of the Fiat dynasty argued with Onassis about business, money and governments.

Like her father, Christina had a relentlessly active mind, but in her adolescent years she lacked his charm and personality, and his self-confidence. Nonetheless, constantly sailing the seven seas, schooled in several languages, through exposure and osmosis she learned the nuances of both high society and high finances. Though her mother was fair and pretty, Christina had inherited her father's darker complexion and larger features. Not a beautiful little girl, she grew prettier as she grew up, and with the help of plastic surgery to straighten her "Greek" nose, she became a pleasant-looking young woman, given to simple clothes and very little jewelry.

Although Onassis was never known to have refused his daughter any request or favor ("Chrsyo Mou," he would call her, "my golden one"), he made it clear to her on numerous occasions that he would only give his permission - when she was ready to contemplate marriage - for her to wed a fellow Greek.

He went even further than that. Following the traditional custom, he selected the man he considered to be a perfect husband: Peter Goulandris. Although Goulandris was an eligible bachelor, young, good-looking and Harvard-educated, none of these attributes mattered to Onassis.

He selected Goulandris because he was Greek, and because his family controlled a number of shipping companies, amounting to billions of dollars, and Onassis had ideas of uniting his family with the Goulandris clan and thereby establishing a great shipping dynasty. There was only one thing wrong with the plan. Because her father insisted that the marriage must take place, Christina flatly refused. She was continuously pressured by her father to relent and marry Goulandris. When he realized he couldn't change her mind, Onassis enlisted the help of his sister, Artemis, and, eventually, that of his new wife and Christina's stepmother, Jacqueline Kennedy, who attempted to be a matchmaker for her stepdaughter, flying all over the Greek islands to hold secret meetings with the Goulandris family, and attempting to talk Christina into the union. It was all to no avail.

The more pressure that was exerted upon Christina, the more she backed away. She began spending more time away from Skorpios and the Christina, away from her father and Jackie, and one day in Monaco, at the swimming pool of the Hotel Metropole, she met a divorced 47-year-old Los Angeles real estate broker by the name of Joseph Bolker. Christina was 20.

Bolker, although old enough to be her father, seemed to be everything that Onassis was not; he neither smoked nor drank, he was a health enthusiast, and his manner was relaxed, calm and quiet.

Within a few days, the two flew to Los Angeles and, without consulting Onassis, announced their impending marriage.

Onassis immediately dispatched Alexander to Los Angeles with instructions to "talk sense" into his sister. When she heard her father's objections, particularly to the difference in their ages, Christina retorted: "Father was over 20 years older than mother when they married. And I love him and will marry him!"

Onassis continued to hope his daughter would change her mind. Despite his threats and entreaties, however, Christina married Bolker on July 29, 1971, in Las Vegas. Onassis was further incensed because Bolker was Jewish. He was concerned that the "guilt by association" he would gain from having a Jewish son-in-law would rupture the delicate Arabian oil connections that were so instrumental to his shipping business.

Onassis cut off all communication with Christina. When she phoned him, he told an assistant: "Make it very clear that I am in . . . but not to her." He also immediately began to make arrangements to cut off Christina's $100 million trust fund.

According to Bolker, he and Christina were put under "extraordinary pressures" by the Onassis family. Just before her 21st birthday, Christina flew to London and attempted to invite her father to attend a party that Bolker was going to have for her in Los Angeles. Usually sentimental about birthdays and holidays, Onassis was intransigent.

But Bolker was beginning to give way. "Christina is a young woman and should not be alienated from her family," he told a journalist. And the Beverly Hills lifestyle was not for Christina. She was bored and missed her family; she longed most to see her father.

Through the pressures of family and friends, and eventually with the enthusiastic consent of Bolker himself, the marriage was dissolved after nine months.

Onassis couldn't have been happier, and rewarded his pet daughter with a whirlwind trip around the world. For the moment, the Onassis family was in harmony.

But in the summer of 1959, Aristotle Onassis had invited Maria Callas and her impresario husband Giovanni Meneghini aboard the Christina for a Mediterranean cruise. Sir Winston and Lady Churchill was taking their annual trip aboard the yacht.

From the moment Callas stepped aboard the ship, neither she nor Onassis had eyes or heart for anyone or anything else. For several weeks, as the luxurious yacht cruised the warm sea with its cargo of emotionally charged people, both Ari and Maria totally ignored their respectives mates, as well as everyone else aboard.

Christina, then only 9 years old, had no specific idea of what was happening. Each time the ship came to port, there was an extraordinary number of newspapermen and photographers waiting, but there had always been a corps of journalists in her father's life and with such renowned people aboard, it seemed very little different from other cruises.

But as the days went on, there was occasional shouting - sometimes sobbing - behind closed cabin doors. The tension over the affair that Onassis was having almost openly with Callas became unbearable for almost everyone on board. The Churchills stayed in their cabins. Tina Onassis seemed to have no way of coping with her husband. Meneghini resorted to hysterical outbursts and screaming fits. Finally, it was decided to end the cruise and head back to Monte Carlo.

The morning the boat docked, Christina was wakened by her mother. Her suitcases were already packed, her books and playthings packaged, ready to go. Within hours, Christina and her mother and brother were on a plane en-route to New York. Tina's marriage to Ari was over; in a few months she divorced him.

Onassis actually pleaded with Tina, "for the sake of the children," to reconsider; but he had no intention of leaving Callas, who quickly divorced Meneghini to free herself to spend all her time with Onassis. As a part of the Onassis divorce settlement, he was given liberal visitation rights to be with his children, so in a matter of months Christina was back on board the ship with her brother and her father. But now there was another woman, in place of her mother.

Christina would never forgive Callas for breaking up her parents' marriage, and refused to be more than superficially cordial.

And as the little girl grew into young womanhood, both Christina and Callas grew to bitterly resent, if not actively hate each other. "Maria never like me very much," Christina said in a recent interview. "She even used to accuse me of trying to separate her from my father." As a matter of fact, Christina was attempting to do just that: It had always been her dream that Tina and Ari would remarry, and Christina had even had discussions with her father to that end.

When Onassis finally severed relations with Callas in 1968 and married Jacqueline Kennedy, instead of remarrying Tina, Christina was deeply hurt. Onassis practically had to beg his 18-year-old daughter to attend his wedding ceremony on Skorpios and she wept openly during the festivities. She also refused to toast the bride and bridegroom, hanging back and seeking comfort from her equally despondent brother. Within a few weeks after marrying Onassis, however, Jackie began a consistent campaign to enlist Christina's friendship. Jackie invited Christina to discreet luncheons, advised her on makeup and clothing, arranged intimate dinner parties for her, even helped her "plan" a new hairstyle and then brought her to Kenneth's salon in New York to have it executed. Within a short while, despite press reports to the contrary, the two women had become, if not friends, then at least passive associates.

Another side of Christina's life was becoming sadly disturbing. Her Aunt Eugenie, Tina's sister, died mysteriously; shortly afterwards, Eugenie's husband, Stavros Niarchos, avidly courted and won the jilted Tina. Christina watched in confusion as her mother married her uncle, who also happened to be her father's arch business rival. Troubled by this new wave of family disturbance, Christina began to seek solace from Jackie.

The teen-aged Christina grew close to John and Caroline Kennedy, and the younger children looked up to their new "big sister." The three were often seen together, Christina frequently wearing only a plain black dress, occasionally being mistaken for the Kennedys' governess.

Christina's security was rocked even more when her brother Alexander died in a plane crash in 1973. Her mother Tina died the following year.

And in March, 1975, came the final blow. Onassis lay dying in Paris. Christina, not Jackie, was at his bedside. Jackie had flown home to New York. Christina would never forgive her stepmother for what she considered such a grave and callous insult to her father.

Within a short while after his death, Christina, who had taken control of the Onassis billion-dollar empire, began plans to permanently abolish all Onassis-family connections with Jacqueline Kennedy Onassis. She wanted Jackie off her island, Skorpios, out of her apartment in Paris. Instructions were given that The Christina was not to be sailed again with Jackie aboard.

Normally, according to Greek law, a widow receives at least half of her husband's estate. Onassis, who had considered divorcing Jackie but died before the marriage could be ended, had legally arranged for her to inherit much less. But after his death, Jackie's lawyers contested the amount, and petitioned for much more. After almost three years of legal negotiations, a financial settlement was reached in late 1977, in which Jackie received $20 million, about one-tenth of what she should have received as the widow of a Greek.

Christina was now in sole control of the vast Onassis conglomerate, at age 24 the richest woman in the world. But with all her great wealth, she remained lonely, unhappy, aloof, unsure.

After her father died, Christina was totally depressed. There have been unconfirmed reports that she attempted suicide. Slowly, she began to pull herself upward from her despair, relying heavily on her remaining family - her great-aunts and uncles, her cousins - and on her father's closest friends and business associates.

Shortly before his death, Onassis had begun to tutor Christina in the nuances of his vast holdings all over the world. Onassis invited her to - and she eagerly attended - every business meeting.

With Onassis' encouragement, she spent much time visiting tanker brokers, insurance companies, shipyards and shipping companies. After her father's death, carrying on his business became her primary concern, almost an obsession.

And almost as a token of respect to the memory of her father, and only four months after he died, Christina married Alexander Andreadis, the scion of a highly respected Greek shipping family whose father owned many banks, one of the largest shipyards in Greece, and the Athens Hilton Hotel.

But the marriage seemed doomed from the beginning. Christina ran roughshod over her quiet, unassuming husband. Headstrong, she did precisely as she pleased, running her corporations for their profit, and refusing to yield the slightest bit of control to her husband or his highly acquisitive family, who had seen the match as a way to at least partial control of the Onassis conglomerate. In a matter of months, they were living apart, and barely more than a year after their wedding, were divorced.

The Onassis fleet, under Christina's direction, has remained profitable and she commands the respect of the management of her corporations, although they disagree with her refusal to diversify.

She has shown surprising maturity, not only in the shipping business but in dealing with the vast Onassis holdings in real estate and industry, and has maintained the worth of the corporation, now reported to be somewhere in the $800 million range.

Recently, she stunned the world by marrying a 37-year-old Soviet shipping administrator. What could Christina, one of the world's richest women, a capitalist par excellence, have in common with a Communist?

"When you fall in love, what does it matter whether you are a communist or a capitalist?" Sergei Kauzov, the man of her choice, said.

Christina is now a handsome, educated (she speaks French, English, German, Italian and some Greek) young woman who has been courted and dated by the likes of Jean Paul Belmondo, Philipe Niarchos (a Greek shipping heir) and Rudolf Nureyev. Skorpios is one of the most enchantingly beautiful spots in the world. She has luxurious apartments in London, Paris, Athens and New York.

But she announced she would live in Moscow. And, bypassing the usual years of waiting, the couple has secured a seven-room apartment. They will also be able to obtain the traditional Soviet dacha - a vacation home in the country. Russia may become Christina's newest retreat, a place she can escape to when the pressures of business become too great. She enjoys and admires her new mother-in-law, who is the highly talented assistant to a Soviet film director.

Christina, like her late father, will always be on the move. Five days after she married Kauzov in a small, private, civil ceremony, she returned to Athens for business negotiations, cutting short her honeymoon in Siberia, beside Lake Baikal, and touching off rumors that the marriage was already on the rocks. (Ten years ago her father interrupted his honeymoon with Jacqueline Kennedy, also for business reasons.)

Kauzov is a linguist, but since he doesn't speak Greek - and she doesn't know it well, either - and she doesn't speak Russian, they converse in English. He has been a shipping administrator for years and is partly responsible for the Soviet Union's recent dominance of the tanker business, while most other countries are suffering economically in that area.

Kauzov is a likable and intelligent man who talks and knows almost as much about the technical side of shipping as Onassis did. Indeed, some friends of Christina claim that although there is no physical resemblance, Sergei greatly reminds her of her father.

This is Christina's first marriage based on love. It seems not to have been entered to prove a point. During the time she spends in Moscow, she will undoubtedly find the kind of privacy she has always wanted. And with Sergei she may regain the family she lost, and build a family of their own. Her first husband, Bolker, said: "What Christina really wants is a home with a baby in the garden . . . and a nursemaid, of course."

And her island, and her yacht, and her apartments, and her limousines, and her $200 million in private assets, including her brand new personal account at the Soviet Bank for Foreign Trade.