Colleen McCullough, shown in 1990, at her home on Norfolk Island. (Patrick Riviere/Getty Images)

Colleen McCullough, the Australian author of the best-selling novel “The Thorn Birds,” an epic story of illicit love in the outback that became one of the most successful television miniseries ever, died Jan. 29 at a hospital on Norfolk Island in the South Pacific. She was 77.

The cause was renal failure, said her agent, Michael V. Carlisle.

Published by Harper and Row in 1977, “The Thorn Birds” was a multi-generational saga that traced a sheep-farming family from 1915 to 1969 and that featured a heroine, Meggie Cleary, who falls desperately and impossibly in love with a Catholic priest, Ralph de Bricassart. It has sold 30 million copies around the world.

At the time of its publication, the novel was compared to Margaret Mitchell’s “Gone with the Wind” — more recently, People magazine called it the “ ‘Fifty Shades of Grey’ of its time” — and sparked breathless excitement among its many female readers, as well as among publishing executives.

Months before the novel’s official release, Avon Books paid $1.9 million — a record at the time — for paperback rights.

Richard Chamberlain and Rachel Ward star in the Emmy Award-winning miniseries, “The Thorn Birds.” (Warner Bros./Hallmark Channel )

The book’s 500-plus pages became the 10-hour TV version that appeared on ABC in 1983, featuring Richard Chamberlain as Father Ralph, Rachel Ward as Meggie and Christopher Plummer as the archbishop. With tens of millions of viewers, “The Thorn Birds” joined such programs as “Roots” and “The Winds of War” in the front rank of miniseries juggernauts.

The whole affair, book and TV show, might never have been if Ms. McCullough had not been allergic to soap.

After what she described as a miserable childhood, she aspired to a career in medicine but was forced to discard that ambition when she developed an intolerance to antiseptic scrub. In the 1960s, her interest in neurophysiology took her to Yale University as a researcher.

Financial worries, along with her grief over a failed relationship, propelled her to start writing there. “I have found that writing is the only thing I can do that obviates that kind of misery,” she once told an interviewer, according to the reference guide Current Biography.

Her first book, called “Tim,” was published in 1974 and became the 1979 movie starring actor Mel Gibson in the title role, a man modeled on one of Ms. McCullough’s patients who embarked on a romance with an older woman despite his developmental disabilities.

Ms. McCullough said that she wrote an early draft of “The Thorn Birds,” her second book, in six weeks while holding down her position at Yale. The title, she said, came from a Celtic legend about a bird that impales itself on a thorn tree “and in its dying agony sings out beautifully.”

“I was midway through writing my book, when I realized this is what my characters were doing,” she told an interviewer in 1977. “You know there are people like that. Their tragedies are self-induced. They bring it all on themselves and are terribly heroic about it.”

In the nearly 40 years since the book was released, few if any critics have cited it as a masterpiece of high literature. Paul Gray, a reviewer for Time magazine, described its “perfervid prose,” replete with exclamations. “What a father you’d have made, Father!” was one of them.

To other critics, fault-finding seemed beside the point.

“To expect ‘The Thorn Birds’ to be a Great Book would be unfair,” Alice K. Turner, best known as the fiction editor at Playboy magazine, wrote in the New York Times. “There are things wrong with it, stock characters, plot contrivances and so forth. But to dismiss it would also be wrong. . . . It offers the best heartthrob since Rhett Butler, plenty of exotic color, plenty of Tolstoyan unhappiness and a good deal of connivance and action. ”

The feminist writer Germaine Greer called it “the best bad book I had ever read.”

The miniseries collected a raft of Emmy and Golden Globe awards and a massive number of fans, although Ms. McCullough was not among them. She called the TV version “instant vomit.”

Nothing if not industrious, Ms. McCullough said that she sometimes wrote as many as 20,000 words in a workday, which could last as long as 18 hours. She produced more than 20 books, including a seven-volume series of historical fiction called “Masters of Rome” and a series of crime stories centered on the fictional detective Carmine Delmonico.

Her book “An Indecent Obsession” (1981) was set in a mental ward of an island military hospital. Some readers found “The Ladies of Missalonghi” (1987) alarmingly similar to “The Blue Castle” by L.M. Montgomery, the author of “Anne of Green Gables,” but Ms. McCullough insisted that the ideas were her own.

Her book “The Independence of Miss Mary Bennet” (2008) was a sequel to Jane Austen’s “Pride and Prejudice.” “Bittersweet,” Ms. McCullough’s final novel, was released in 2014.

Colleen Margaretta McCullough was born June 1, 1937, in Wellington, in New South Wales. The family moved frequently to find work for her father.

“Get out and get a job as a mangle hand in a laundry,” she recalled her father telling her. “That’s all you’re good for — you’ll never get a husband, you’re too big and fat and ugly.”

After university studies in Sydney, she worked in London before landing at Yale, where she stayed for a decade in the 1960s and ’70s.

Ms. McCullough infused her fiction with some of her own experiences, including the loss of her brother, who rescued two women from drowning and then died in what Ms. McCullough suspected was a suicide. Dane, a character in “The Thorn Birds,” dies under similar circumstances. Besides her fiction, Ms. McCullough wrote a memoir, “Life Without the Boring Bits.”

Survivors include her husband of three decades, Ric Robinson; two stepchildren; and two grandchildren.

Ms. McCullough said that she amassed a library that included several thousand books on ancient Rome.

“Like Caesar, I think it’s an eternal sleep,” she told an Australian interviewer, referring to death. “I don’t think there’s anything to be scared of.”