The windows are open in the rented car, and Conroy silently considers the monstrous mansions, the hissing, well-clipped lawns and remote-controlled wrought-iron gates enjoyed by some of the most conspicuously wealthy homeowners on the planet.

"Ladies and gentlemen, " he tells the other passengers, "I have an announcement to make. I'm not going to be a weenie anymore."

In 1979, when he made that Declaration of Impending Importance, Conroy had written one moderately successful novel, "The Great Santini." In the spring of 1988, Conroy is probably the best-known writer of serious fiction in the Southeast, a region with no shortage of literary talent. His third novel, "The Prince of Tides" published in 1986, is a 250,000-selling blockbuster, and Conroy is no weenie.

At age 42 Conroy is not only doing well for himself, but he also has entered territory trod by very few - he is now a writer who can help make publishers and booksellers wealthy.

"The minute we had the manuscript and read it, we knew we had a chance to mak e this the biggest book we'd published in some time, " says Steven Lewers, vice president and director of marketing and sales at Houghton Mifflin Co. in New York. Conroy's book subsequently outsold every other Houghton Mifflin hardback since "The Silmarillion, " J.R.R. Tolkien's 1977 posthumous best seller, Lewers says.

"The wheel is turned, " says Faith Brunson, who has bought books for the Rich's department stores for 30 years. "They [book sellers] are now dependent on [Conroy] instead of the other way around. They will court him and court his publisher."

That kind of clout won Conroy a million-dollar contract from Houghton Mifflin for his upcoming book before he'd written a word (the title and much of the subject matter are as yet undecided), and helped boost the bidding on the paperback rights for "The Prince of Tides, " which sold for $1,313,500 last Thanksgiving. United Artists bought the movie rights for $850,000, and Robert Redford has expressed interest in starring in the film.

With the publication of "The Prince of Tides, " public adulation and folding money began raining down on the Atlanta author like confetti at Mardi Gras. Conroy says he saw evidence of the biggest switch in his fortunes when he was on the promotional tour, helping to sell his story.

"The Prince of Tides' changed everything, " Conroy says, sitting in the carriage house studio behind his Brookwood Hills home. "When I went to autograph parties, there were people there. With my other books you could fire off a pistol around my table and not be in danger of hitting anyone."

As his banter demonstrates, none of Conroy's more endearing qualities has disappeared with his new status. He is still a master of the art of gentle self-deprecation; he will not brag on the brass ring, even when he's got it firmly in his fist.

He won't be investing in Giorgio Armani suits, either. Despite his years of living in Rome and touring through Paris, Conroy's sense of haute couture runs to moldy sportcoats and gangrenous Top-Siders. When he addressed the American Booksellers Association in 1986, he wore a jacket that one observer wryly judged to have been dipped in oatmeal. But, wedged between celebrity speakers, Conroy, in his stemwinding fashion, stole the show. "He blew Walter Cronkite and Carol Burnette out of the water, " says Conroy's New York literary agent, Julian Bach.

If the good times have changed him, it's most noticeable around the waistline. He has put about 30 extra pounds on his 6-foot frame, weight his doctor wants taken back off. Certain stressful events of the recent past have turned his salt-and-pepper hair to mostly white. But he still has that Cabbage Patch grin, stitched into a face like a dissolute choirboy.

And he is still, through fiction, trying to explain his own life to himself. The son of a Marine fighter pilot, Conroy attended 10 different schools in 12 years and grew up accustomed to life as an outsider in one Southern town after another. Accordingly, his books have tried to recapture a South that never belonged to him. "I always feel like I have to justify the Southern thing, " he says during a rambling conversation on a mild spring afternoon, "and yet it is important to me. I'll certainly try again in this new book. The South is an obsessive theme with me. It might be because I somehow do not feel that I'm an actual part of it."

As a child tyrannized by both parents, Conroy grew older without having a chance to be young. Therefore, his books return to adolescence, as if in restating the pain of his own youth, he can exorcise his explosive anger and capture a childhood he never lived.

"Anger has been the complete motivating force of my writing career thus far, " he says. "I think it comes from being the son of a violent man. . . . I think my way of dealing with it is writing about it."

If you've read Conroy's books, you've already lived a little of Conroy's life. In "The Great Santini, " he gave us one of fiction's most unforgettable characters, a scenery-chewing, cuss-roaring legend named Bull Meecham. Meecham was the toughest Marine to wear leather, a man between wars who expended his unused fury whipping his eldest son into shape with the screaming ardor of a drill instructor.

Conroy says Meecham isn't even a patch on the real thing: Marine fighter pilot Col. Don Conroy, "the most fearsome son of a bitch in the world."

Today the Colonel's military posture is hampered by arthritis, and he needs a cane to move from his car into the Original Pancake House, where he's taking a late breakfast. The years have hobbled and mellowed The Great Santini, though at age 66 he confesses himself still unsuited for peacetime. "I feel like something's missing, " he says, describing his combat tours in World War II, Korea and Vietnam, and ordering oatmeal and coffee.

Seated, the Colonel's 6-foot-2-inch frame is still forbidding, yet he chooses his words with great delicacy as he disputes the portrait painted by his son. When he first read "The Great Santini, " Don Conroy was enraged; he saw himself characterized as a child-and wife-beater who bounced basketballs off his eldest son's head.

"Pat would say it was 100 percent the truth, but I will tell you nothing could be farther from the truth, " the Colonel says. "Pat will take an incident and embellish it. I know about the incident, but I don't know about the embellishments."

While the father views Santini as a creature exaggerated to serve the needs of fiction, the son says the beatings were real. "His feelings were hurt when 'The Great Santini' came out, there's no question, and I'm sorry about that. That's bad, " the author says. "But nothing that I write will ever be as bad as a ruined childhood. He stole my childhood."

With "The Great Santini, " Conroy reclaims his childhood, and, by pouring out his rage, claims the right to love his father. He says the book finally brought the two closer together. The Colonel agrees, saying that he eventually realized "it's a love story from a boy to his father." Now Don Conroy proudly displays a vanity front-bumper tag on his station wagon that reads, "The Great Santini."

Pat is the eldest of seven Conroy children, many of whom still live in South Carolina. That state came the closest to being a home for the family when the Colonel settled in the antebellum coastal town of Beaufort, S.C., during Pat's last two years in high school. The action of "The Great Santini" takes place there.

According to reports from his friends and teachers, Pat Conroy blossomed during those two years at Beaufort High, his first education outside Catholic schools. He had played basketball with black athletes in an integrated parochial school in Washington, D.C., and the capitol city kids were good role models on the court. Down in sleepy segregated Beaufort, he dazzled the all-white varsity squad.

Conroy was eventually chosen senior class president. A popular student, he still was rather shy and conservative. "Very Catholic, very patriotic, " remembers Bernie Schein, a schoolmate who became a great buddy. "He didn't want to hang around with us because we drank and smoked and dated, " says Schein, now an Atlantan. Pat didn't have a driver's license until he was 20 years old, because his father didn't think teenagers should drive. William Dufford, who was principal of Beaufort High School at the time, says, "I believe Pat thought if he had a driver's license, he might have to date a girl."

J. Eugene Norris, Conroy's English teacher who appears in "Santini" as the teacher Ogden Loring, remembers the young man as a voracious reader and a natural writer whose prose was a "little bit flowery, though it ticks him off when I say that."

Norris gave Conroy a copy of "Look Homeward Angel" and triggered an abiding infatuation with the high-flown prose of Thomas Wolfe. One summer they drove together to Asheville, N.C., to visit Wolfe's boyhood home. Conroy confesses that back then, he aped Wolfe's style so often he should have been tried for plagiarism.

As a high school senior, Conroy wanted to attend Duke University or the University of North Carolina at Chapel Hill. "When they found out how much it would cost to send me there, my parents just laughed, " he remembers. Then the boy leaned toward Newberry College in South Carolina, but the Colonel nixed that choice when he discovered it was run by Lutherans.

Along with his literary ambitions, Pat Conroy harbored a desire to become a Marine aviator, to beat his father at his own game, so with the Colonel's blessings he entered Charleston's Military College of South Carolina - The Citadel - in 1963. His myopia and colorblindness shot down the possibility of a flying career, but as an aspiring writer, Conroy couldn't have picked a better setting for the harrowing, violent drama that would surface in his second novel, "The Lords of Discipline." "I thought my father was rough, " he says, "but I was unprepared for the plebe system at the Citadel."

The Citadel administration failed to make Conroy into a soldier - he graduated as a lowly private - but succeeded in making him into a writer through the familiar spur of outrage. His favorite administrator, Lt. Col. Thomas "The Boo" Courvoisie, was demoted and barred from contact with cadets. Ten years before "The Lords of Discipline" was published, an angry Conroy wrote a slim non-fiction account of Citadel life called "The Boo" as a tribute to Courvoisie.

He started writing "The Boo" in the fall of 1969, two years after graduating from The Citadel. During those years he taught English and coached basketball at his old high school. His Beaufort home was a carriage house on the grounds of a larger residence. In a similar cabin next door lived Barbara Bolling Jones.

When they met, she was the mother of a toddler and was pregnant with her second child. Her husband had just been killed in Vietnam. Conroy's instinct was to help and protect the new widow, and their friendship grew into courtship.

"I think he was a little innocent about women, " Barbara Conroy says now. She ascribes that naivete partly to Conroy's Catholic-inspired guilt and partly to a relationship with his mother that she describes as "complex."

It wasn't until a day or so before the wedding that the future Mrs. Conroy met the dominant woman in Pat's life. "She wore a bright blue velvet suit, and she was really beautiful, " Barbara Conroy remembers. "When I first met Pat's mother, she was younger than I am now, and she looked like a movie star."

Around that time the Colonel returned to Vietnam for another tour of duty, and Peg Conroy and her children - Tommy, the youngest, was in grade school - moved to Pat's neighborhood in Beaufort. At age 40 she appeared so youthful that there was confusion in the town as to which Mrs. Conroy was Pat's wife and which was his mother.

Conroy later lauded that beauty in "The Prince of Tides, " a novel in which the lovely and manipulative Lila Wingo inspires both erotic reverence and bitter resentment in her son Tom. While Conroy was writing the book, his mother was dying of cancer.

As "The Great Santini" was his father's book, "The Prince of Tides" is his mother's. It liberates Conroy's anger at his mother and serves as a tribute to her. It is also the story of Savannah Wingo, Tom's beautiful, psychotic sister, who is modeled on Conroy's oldest sister, New York poet Carol Conroy.

The real-life brother-sister relationship has not proceeded as happily as the fictional one. "I think that she feels I have stolen her life, " Conroy says. "She told me, 'You can't write about me.' I said, 'The hell I can't.' " Conroy says his sister hasn't spoken to him in four years, and refused to allow her poems to be used in the novel as examples of Savannah's writing.

Nor was that novel an occasion for a resolution of the tension between mother and son. Peg Conroy died before "The Prince of Tides" was published, and Conroy says it's probably for the best. "I was horrified to see my mother die, " he says. "I was not unhappy that she was dead when this book came out."

The woman that Conroy has dubbed "Queen Lear" still baffles him, he says. "My mother I will never figure out. She is too much woman for me, and I am not enough writer for her."

During the fall and winter of 1969 and the spring of 1970, Conroy left his new wife Barbara behind in Beaufort each weekday, negotiated a 90-minute commute over land and water to impoverished Daufuskie Island and taught in a two-room schoolhouse, the only white person in an all- black universe.

It would be his last real job. In his zeal to educate the island children, he clashed repeatedly with school administrators and was fired at year's end. Conroy was once again enraged by the world, and once again turned that rage into a book. While he was publishing "The Boo" through a vanity press, he fought his dismissal in the courts and began writing another book about his life as an island teacher. He completed "The Water Is Wide" with the help of a Ford Foundation grant, and it was published by Houghton Mifflin in 1972, around the same time the Conroys moved to Atlanta.

"The Great Santini" came next in 1976 and "The Lords of Discipline" in 1980. Conroy was a young writer who had survived enough turbulence to fill several lives, but the interesting times were not to end soon.

As his reputation grew, his relationship with Barbara unraveled. Ms. Conroy is reluctant to discuss this period, saying, "I have a tendency to make it sound like it was his fault." She chooses instead to remember his generosity, noting that he paid her tuition at Emory Law School and supported their three children - her children, Jessica and Melissa, whom he adopted, and their daughter together, Megan - while making a living as a writer of fiction.

The rigors of life as a writer certainly contributed to the tension. "He would go forever not writing anything, then go into fourth gear and write day and night, " she says. "He would go off for a month sometimes to hole up and write. . . . In those times he was pretty remote."

In true Conroy style, he transformed the pain of their eventual divorce into more work, writing a piece for Atlanta magazine about the breakup, in which he captured the chilling, destructive nature of this 20th-century disease. "Each divorce, " he wrote, "is the death of a small civilization."

On April 16, 1980, on a blind date arranged by Bernie Schein and his wife Martha, Conroy met a dark-eyed woman named Lenore Gurewitz Fleischer. They had drinks at a friend's apartment and heard Cleo Laine sing at Chastain Park. They dated for a year. One day in March 1981, Conroy called up Ms. Fleischer and said, "If you're not busy Saturday night, I think we should get married." They had known each other for 11 months. "It took that long just to learn each other's children's names, " quips Jim Landon, Conroy's attorney and a friend, who lent his condominium for the wedding.

The family now includes Lenore's children, Gregory and Emily, and their child together, Susannah. Three Conroy kids will be in college this fall (Jessica, Melissa and Megan), and when Jessica graduates, Gregory will matriculate. Lenore says, "They all just love expensive schools."

Instead of boats and vacation homes, Conroy buys education. The one indulgence around his handsome brick home is the stack of Mont Blanc pens on his desk - he writes his books in longhand.

Conroy is fiercely protective of his children, as if to give them the peace that he never knew. That tranquility was breached by a new series of misfortunes centered around Alan S. Fleischer, a neurosurgeon, a former teacher at the Emory University School of Medicine and former husband of Lenore.

After their divorce, Fleischer kept Lenore in court, seeking custody of their children. His meetings with Conroy erupted into violence, prompting a suit from Fleischer charging assault, and a countersuit from Conroy charging harassment.

Then, in the summer of 1981, Conroy moved his entire family to Rome, Italy. He told friends that he went there for the culture, for inspiration. The real reason emerged in the fall of 1985, when a DeKalb County grand jury indicted Fleischer for child molestation. Unable to gain full custody of the children in court, Conroy protected them by putting an ocean between them and Fleischer.

Fleischer had already relocated to Tucson, Ariz., when DeKalb County issued a bench warrant for his arrest. According to DeKalb County Assistant District Attorney J. Tom Morgan, that warrant is still outstanding, though the state of Georgia will not seek extradition. The Conroy family moved back to Atlanta permanently last summer.

The stress from that saga, the ordeal of his mother's slow death from cancer and Conroy's own bibulous habits (a taste for wine, spirits and sometimes 20 cups of coffee a day) brought him to a health crisis this year. After exploratory surgery revealed an extraordinarily inflamed stomach lining, his doctor put him on a strict regimen: no fats, no alcohol, no caffeine. "He cut out all major food chains, " Conroy says. "I said I would do anything he asked as long as he wouldn't put that tube up my nose again."

Other milder annoyances seem to have a bracing effect on the contentious author. This year a fundamentalist minister in Charleston denounced Conroy's latest novel as pornography, and the Charleston News and Courier chimed its agreement . Conroy entered the fray with vigor, penning an acidulous letter to the editor that called into question the pedigree of both preacher and paper.

In Conroy's books, South Carolina and its people are the heroes. But the real residents of the Low Country haven't always accepted the compliment graciously. When The Citadel refused to allow the movie version of "The Lords of Discipline" to be filmed on campus, Conroy wrote to a reporter friend, "The Citadel as a school and Conroy as a writer are both terrified that it will be discovered that we are mediocre and second- rate."

Conroy still fears discovery - a victim, he says, of the Impostor Syndrome. This version of Conroy, the boy who "never spent a single day in a hometown, " is still looking for social acceptance, still competing with his father. Under this guise, he describes his empurpled, Wolfean prose as the best he can do.

"I only write the way I can, " Conroy says. "If I could, I would write like Hemingway. My personality comes out in my books. You can dip into my books and dip into me. And enjoy me or loathe me."