When last we looked in on Colleen McCullough, she had escaped from her job as a technician in a neurophysiology lab at Yale University by writing a best-selling novel, "The Thorn Birds," set on a sheep ranch in her native Australia. With millions in the bank, but no love in her life, she sailed away to Norfolk Island in the South Pacific.

As today's episode begins, we find in the ensuing decade or so the hitherto self-described spinster, now 52 years old, has: found true romance on the island; cast aside her image as a teller of tales mostly about lovelorn women; and, transformed into an erudite scholar, written "The First Man in Rome."

The story, first of a projected series of novels on plebeians and patricians, battles and bawdry in republican Rome, goes exhaustively into the conflicts, conspiracies and copulations between the old aristocracy who have no money (represented by Lucius Cornelius Sulla) and the wealthy upstarts who have no position (personified by Gaius Mallius Marius). Both advance through military campaigns, convoluted conspiracies and marriage (both wed daughters of Gaius Julius Caesar, grandfather of the Julius Caesar). All this happens in a bit more than a decade, from 110 B.C. through 100 B.C.

"When I decided to do a historical novel, I thought, this is a period no one has done," McCullough said the other day in her Ritz-Carlton Hotel suite. "I actually worked out the novel about the time I did 'Thorn Birds.' I carry novels in my head a long time.

"I first thought I'd do a single book about Julius Caesar. Then I realized that the period was too juicy, too meaty, too bitter and nasty for just one book," she said. "So I decided to write a series, like a sort of Roman 'Forsyte Saga.' I like to think of this book as the first chapter."

McCullough spent 13 years doing research for the planned sextet (an appropriate word in more than one sense), bringing an entire library on Roman history to her remote island.

The 896-page Big Book is the only novel this season to come with a 111-page glossary and pronunciation guide, as well as maps and portraits of the characters, drawn by the author from photographs of Roman busts. "The First Man in Rome" also has been recorded on four cassettes by actor David Ogden Stiers.

"The glossary -- lots of dirty words -- took four or five weeks; if I had been a professional scholar it would've taken a year," she said. "I had the nucleus of what I needed for the book, 180 Loeb classics from the Harvard University Press -- Latin on one side, English on the other. The 1914 translations are rather quaint: 'Morally depraved,' they say, when we'd translate it as 'so and so interfered with little boys.' Latin called a spade a spade."

At least one authority says her research shows. In a review in the Ottawa Citizen, Trevor Hodge, of the Carleton University department of classics, wrote: "Academics in particular will have pre-judged the issue, and will open the book at all only for the fun of sneering at the author of 'The Thorn Birds' trying to be a Roman historian, and falling flat on her face amid howlers of every sort. Unfortunately, she doesn't."

But Hodge goes on to criticize the prose as being "on the level of creative writing in Grade 11." Indeed, despite the glossary, the book is full of anachronistic cliches -- "grass widows," "did not sit well," "not up to," "a good show," "electrified" and more.

For instance:

" 'Young men are boring, they remind me of my brothers. I would much rather marry someone like Gaius Marius,' said the scholarly daughter {Caesar's daughter Julia}. 'I'll be good to him, I promise. He will love me, and never regret the expense.'

" 'Whoever would have thought it?' asked Caesar, of no one in particular."

"Well, I wasn't writing in Latin, mate," McCullough said. "The roots of all these words are Latin. I tried to write in good standard English prose. You can't get away from idiom."

With her bluff, hearty manner, McCullough is a formidable presence. Her lavish, colorful clothes, made for her in Australia, are well suited to her orange hair and 5 feet 10 inches -- with proportions to match. She chain-smokes without apology. Though she moves with determination, McCullough complains she has aches in her bones.

McCullough was born in 1938 in Wellington, New South Wales. Her parents were poor, and, she says, they couldn't afford to pay for her to study to be a doctor, but she did go to the University of Sydney and worked at enough different sorts of jobs to give her a good background for her novels. She taught in the Australian Outback, drove a school bus and worked as a librarian before she trained as a medical technician and moved to New Haven, Conn.

Then in 1977 the paperback edition of "Thorn Birds" sold 7 million copies (the hardback half a million), well-justifying her $1.9 million advance, a record for the time. The story also became a television miniseries, and according to Maclean's magazine, McCullough reaped $5 million or so from the Outback epic.

The writer's success freed her from money worries, though not from other kinds.

She once told the Brisbane Courier-Mail: "Four of my five novels have unmarried women as heroines or villains. The life I gave Missy {in "The Ladies of Missalonghi"} is based on my own experiences and those of my mother, who really had a tough time of it.

"Let's face it," she said. "I'm no Miss Australia to look at. And it was because of my own personal experience that I have had a particular fascination with the old maid."

McCullough didn't marry early in life, she said here the other day, because: "I would never put myself in a position like my mother's -- the humiliation that husbands of my father's age put their wives through ...

"The wives had no independence. I listened to my mother and father and decided 'not for me.' I vowed I'd never marry. I was a spinster -- I had boyfriends, sure, but I'd never let them stay the night."

McCullough is especially scornful of male academic types such as those she met at Yale. "When I think of academic geniuses I could have married but was too smart to! When men earn higher degrees their {word with an Old Norse root} drop off. They lose that quintessential masculine quality. I don't mean macho -- that's fake."

Even so, the author isn't the man-hater some people presumed from "Thorn Birds." In some of her other novels, an older, professional woman is attracted to a craftsman or a man not her intellectual or social equal.

McCullough now says, "I don't care how famous or intelligent you are, it's lovely to lean on a man." She prefers men who work with their hands -- "you can lean on them and they don't fall over." She gave that laugh of hers, more bronchial than belly.

McCullough's own husband sounds very much like she wrote him instead of met him. "Like most people on Norfolk Island, he's a descendant of the crew of the Bounty," she said. "He's a colonial aristocrat -- a cross between Isaac Newton, a Samoan prince and a convict." Not to mention he's "good company. He's my sounding board. He doesn't criticize; he's not a talker, but I bounce it all off on him."

She looked enormously pleased at the thought of him. "I think I was fated to go to Norfolk to meet the only man I could ever marry," she said. She moved to the 15-square-mile volcanic island 1,100 miles east of Australia in January 1980.

"I was afraid to live alone in New Haven, though I had for years," McCullough said. "When you're rich and famous, you can't live on your own -- rape, kidnapping, burglary -- all those things are possible. So I set out to find a safe place."

McCullough has always felt safe on Norfolk. "For several years, I lived there totally alone and never locked a door. I still don't lock up. I leave the keys in the ignition of the car, but don't leave an electric drill or sander alone. Tools are the only things that aren't safe. That comes from the days when they were scarce, and everyone used them in common."

She met her husband, Ric Robinson, when he came to paint and plaster her house. One friend marveled that she was fortunate enough to find Robinson, and McCullough retorted that some women might overlook their house painter.

"Some of the Norfolk people are terrible social snobs. One of the retired British colonial servants said, 'Don't you miss intellectual companionship?' And I said, 'Dearie, when the typhoon blows the roof off your house, which had you rather have, an intellectual or a roofer?' And she had to admit I had something there."

McCullough pointed out with pleasure that "he doesn't have to ask his wife for money either -- he's independent."

He also is a member of the local parliament. McCullough is chairman of the hospital board (and the principal tourist attraction). To hear her talk about the demands Australia makes on Norfolk -- "they treat us like a colony" -- you'd think she was talking about Congress and the District. The island has been a tax haven, thanks to its administrative status with Australia.

"It's not a paradise," McCullough demurred. "No place is paradise when there's more than one person on it. Norfolk has 2,000. In a city you live in a vacuum, but with so few people, you know too much about each other. If you see the police car in front of a house, everybody has their version of why. You have to be weird to live there.

"No, I'll never write about Norfolk Island," she added. "I want to live there."