The Irish writer, who died last week at the age of 77, considered himself a failure as a young man because he could not pass the exam required to gain a place at Queen's University, Belfast.
However, if Moore had passed, he would probably have become a doctor like his father, instead of a major 20th -century writer, according to the author Patricia Craig, who conducted many interviews with the novelist for his official biography, which will be completed this year.
Ms Craig is convinced that the literary standing of Moore, who was shortlisted for the Booker Prize three times, will become higher as people now begin to reassess his work. "Until now the strength and energy of his narratives has overshadowed the skill and elegance of his writing, but I think that is about to change," she told The Independent on Sunday.
Moore was born into a large Belfast family but, despite his Catholic upbringing, was a natural agnostic who admitted to drawing on his early life as a metaphor for the many forms of belief addressed in his work.
"Like many people he reacted against his Belfast background, particularly the Irish nationalism that was forced down his throat, but he never really broke with it," said Ms Craig. "Because of the exam, he tended to associate Belfast with a sense of failure and that came out in his writing."
Moore left Belfast in 1943 and served with the British Ministry of War Transport during the Second World War before emigrating to Canada in 1948.
He fine-tuned his writing abilities on the Montreal Gazette, where, according to contemporaries, he was considered the best reporter the newspaper had ever had.
When his first short story, Sasanach (sic), was printed in a low-circulation Canadian literary magazine, he regarded it as a major breakthrough.
Moore told Ms Craig: "This little magazine came out and I remember going down to a cafe called Honeydew and opening it. It was amazing - I was just so chuffed, it was fantastic."
The boost to his confidence led him to write a string of paperback thrillers to fund his retreat to the Laurentian Mountains, north of Montreal, where he wrote his first novel, Judith Hearne, which later became The Lonely Passion of Judith Hearne.
Judith Hearne was published in 1955 and Moore followed his initial success with 19 further novels. According to Ms Craig, Moore's choice of subject matter was driven by his desire to "write about something he knew from the inside, rather than as a spectator".
"He had seen the Germans fleeing Naples and was at Auschwitz when it was liberated yet, despite all the things that had happened to him, his first serious novel was about a Catholic Belfast spinster losing her faith in the stagnating quagmire of provincial life."
In his own life, he eschewed literary circles and big cities, preferring to stay at home and get on with his work. He shared a love of wild landscapes and isolation with his second wife Jean. For the last 30 years, the couple lived right outside of Malibu, a 16-mile drive from the nearest shop.
Moore once told Craig: "I think I have had a very happy career as a writer. I wasn't done in by all those classic Irish things like drink, religion and begrudgery."
He remained an Irishman to the last, however. His last piece of writing, an autobiographical essay on Ireland, told of how he wanted to be buried there, in a particular field in Connemara facing the Atlantic, "a quiet place among the grazing cows".Reuse content