`Nineteen -eighty was not the end of a golden age, but it was certainly the end of an era." Lilian Roberts Finlay is 83. She was born during the First World War. She can remember opening the door for Yeats when she did her acting training in the Abbey. She lost two sons from meningitis during the second World War. And now she has written a novel set in 1980. "I feel if you knew Ireland before 1980, you knew a different place," she says in her elegant modulated voice. Cassa is about a young woman who has led a sheltered life and finds herself suddenly, in her thirties, forced to enter the working world. The book was closely researched: "I'm a gatherer, nothing ever gets thrown out."

We are sitting in her cosy sitting room in her house in Dunsany, surrounded by books. Down the hall she keeps stacks of newspapers and magazines: "Twenty years ago, rape and all sorts of things were never reported. Nowadays they are part of the daily news. 20 years ago, a woman in her thirties assumed she was on the shelf. The word `spinster' was used then. Today all that has changed as well." In the 1980 world of the novel, Cassa refers to herself as a washed-up "spinster" at the age of 34 (and definitely too old to have a baby). But this particular spinster nearly becomes her brother-in-law's mistress and ends up falling in love with a priest. Like Lilian herself, the book is full of surprises. "That situation was terribly real for me. I fell in love with a priest. I was married at the time. It was during the 1970s," Lilian confesses. "Alas, he decided to stay in the priesthood." Most of her writing is based on her own experience (her first two books, Al- ways in My Mind and Forever in the Past, are autobiographical). Cassa is forced to take a job as a cleaning supervisor in a hospital and her experiences are directly based on a year Lilian spent doing the same job, when finances were particularly tight. "I had led a very protected life. That is to say, I hadn't mixed with people out of my class, for want of a better word. When my day ended at the hospital I would write down everything the women had said. All their talk was new to me." In the novel, Cassa comes to know about the tough lives the cleaners lead, from Rita Clarke, married to a drunk whom she still loves, to Margaret Riley, the girl who takes her own life because of abuse she suffered from her father. There is plenty of banter and humour as the women slog through their work: "Yer woman is on the monopods! It affects the memory - it's the hot flushes: sends the blood to the brain!"

Lilian's first desire was to become an actress: "I worked in the civil service by day and studied at the Abbey at night. I remember Yeats, and O'Casey too - they were all knocking around in the 1930s." She loved her time there but, just as she leavens the romance in Cassa with hefty doses of the gritty reality of poverty, she does not romanticise how life was for the ordinary person then.

"There were too many children and no birth control. You wondered how Protestant couples only had two or three children. It was some magic you didn't know about." Her own marriage resulted in a a big brood, and her yen to write plays was shelved in favour of the more lucrative pickings available for short stories and articles. Although her husband Hugh had a good job with Aer Lingus, with so many children to feed and educate, money was tight: "I always wanted a big family and was mad about them. But I had wanted to write for the stage, for honour. I ended up writing romantic stories for tuppenny magazines in England. The £5 I got for each story bought us meat and vegetables for a week." Her style was, of necessity (and because of the draconian censorship laws), "innocent, banal and vaguely optimistic". It wasn't until 1983, when her youngest was old enough to go to college, she realised she had time at last to take on a more substantial writing project. Always in My Mind was published the following year. She has also published a collection of short stories and another novel, Stella. Stella was written as the result of another period of financial hardship: "My husband died suddenly. He was a lovely man who never worried about money. I discovered I had £4 in the bank. After his retirement we bought this house in Dunsany, and he had poured his lump sum from Aer Lingus into the house, which was a shack and needed a lot of work." She answered an advertisement in The Irish Times for a nanny, saying she was 69 ("I was 69 for a long time"). In reality she was well into her 70s, but then as now, looked much younger: "I thought if there is one thing I can do, it's look after children. My employers were multi-millionaires living in Philadelphia. They wanted a plain woman for their nanny because the husband had got all their other young French and Swiss au pairs into bed."

Lilian spent nearly a year there, packed with adventure: "He was a drug peddler," she says matter-of-factly. "We were in the car one day and it was lined with the stuff. I got shot. She (the peddler's wife) was high and she thought I was going to tell the police." Lilian returned to Ireland armed with the material for Stella: "It was a very successful little book." Our conversation returns repeatedly to her grown children, how they went to university on scholarships and scattered around the globe because of the lack of jobs in the late 1960s and early 1970s. Fergus, ex-Labour party spin doctor, lives in Ireland, but his twin, Finola, lives in Vancouver. "She works in higher education with a brief to the British Colombian Senate. She has done very well." Thanks to Finola, Lilian was invited to the Vancouver Writers' Festival last month: "I went with Maeve Binchy, who is a dear friend. Maeve's genius is special. She has a love of people and a humour that is never divisive." Although she does not write in the literary genre herself, Henry James is Lilian's most admired writer. "He's my god. He had such a depth of understanding of women. His work seems as up-to-date nowadays as it ever did, about how people work and what makes them tick."

SHE is also a big fan of Kate O'Brien: "The love scene in Mary Lavelle between Mary and Juanito must be the most wonderful I've ever read. That book was censored and Kate O'Brien was told never to come to this country again. It must have been terribly frightening for her. I remember my cousin giving me another Kate O'Brien novel, The Land of Spices, also banned, with the warning: `You better not let anyone know you're reading this - it's forbidden.' She had bought it in England." Cassa is dedicated to another figure who is special to Lilian: her grandmother, a Dublin woman with the magnificent name of Bedelia Brabazon. Lilian was one of two twins, but the other twin did not survive, and throughout her childhood, she felt "like half a person". It did not help that her mother made her feel unwanted and her father (a professional soldier from Wales) had died at the front.

Her mother got remarried when she was nine, to a man who was, says Lilian tactfully, "interested in little girls". When her mother got wind of what was going on, Lilian was packed off to boarding school in Mount Sackville. "My grandmother was my only visitor. Every Sunday, she would walk through the Phoenix Park to the school, carrying a bag of sweets. She was devoted to me." Meanwhile her mother was being "beaten nearly to death" by the new husband. Listening to Lilian talk about her mother - a beautiful, cold woman - I am reminded of Cassa's unpleasant sister, Nicole, in the new novel. Any connection? "No doubt, although this is the kind of thing I only recognise after I've written a character. "Writing removes burdens from your mind. You solve things. You realise how it should have been. It's the supreme catalyst."

Cassa (Brandon/Mount Eagle, £9.99) was published last week