LIKE DAVID WALKER and Malcolm Lowry, Brian Moore is frequently discussed as a Canadian writer. While living in Canada from 1948 to 1959 he produced his first three novels, some of his best; the last, The Luck of Ginger Coffey, being set in Montreal. Although he has lived for the last three decades in the United States, he has maintained his Canadian citizenship. His "non-fiction novel," The Revolution Script (1971), examined the October Crisis. A McGill professor is the central figure in The Great Victorian Collection (1975). Black Robe (1985) is based on the l7th-century Jesuit Relations. When he served as writer in residence at the University of Toronto in the fall of 1982, he told a student interviewer: "Canada is one of my fictional territories. I`ve lived in Canada long enough to feel that it is one of the places that I can write about with some authority. The other places are Europe and America. I feel I write about these places with less authority than I do about Canada and Ireland. I can`t explain why. Irelands logical, but Canada is something else. It is in some ways my second home, if not actual." In Lies of Silence, his latest (his l7th) work, there is one character who is Canadian. Moore gives us nothing of her Canadian life or background. We have, in fact, little sense of her as an individual. This thin characterization is probably deliberate; although she is a pivotal character, necessary for the action, she is functional rather than individual. Moore concentrates, rather, on two worlds: the outer world of Belfast and the inner world of Michael Dillon, product of that city of Northern Ireland. The concern for "special security" in the opening pages prepares us for a world where the population lives in a "state of siege," where fear and panic are normal reactions, and where "Safe home" is a fitting leave-taking. The drive from the hotel Dillon manages, which was bombed the year before, to his house, watched by ominous strangers, takes him through "graffiti-fouled barricaded slums where the city`s Protestant and Catholic poor confronted each other, year in and year out, in a stasis of hatred, fear and mistrust." After a quarter of a century of civil strife between the IRA and UDA, and "lies of silence from those in Westminster," Michael asks, "Why do we stay here?" The novelist makes no comment. This Belfast is presented only through the consciousness, the limited perspective of this typical Moore protagonist, "hero" or victim: isolated, rootless, uncommitted, no longer believing in his own integrity, who, having lost his faith in God and himself, lives in a spiritual void, aware of what Moore calls "the ultimate meaninglessness of life." We accompany Dillon through the crucial week of his life, when he, like other characters in Moore`s fiction, is forced to confront the validity of the illusions that have been necessary to his daily existence. Dillon is "a failed poet in a business suit:` who, partly through his ego, has made the wrong marriage to Moira, an anorexic whose beauty is fading. Dillon has fallen in love with Andrea, a Canadian just out of graduate school. He is consumed with guilt, but having made no declaration to his wife, he lives with his lies of silence. He is steeling himself to strike out, to recover his lost integrity, to tell Moira of his almost immediate departure for London with Andrea, when the outer world, the political violence of Belfast, suddenly invades his private world. Masked louts of the IRA take over his house. His enforced participation in a bombing attempt on his own hotel, endangering Moira`s life, leads to moral confusion. The lies of silence are now political as well as personal. Hoping to leave the physical and moral chaos behind, he flies to London with Andrea, to what seems at first to be a new life. But, of course, there is no escape. The bloody world of Belfast pursues him across the narrow sea. In a moment of "blind anger:` triggered by the conniving of a priest who has tracked him down, he makes a choice, to tell the police, to end his lies of silence, to make a commitment that will restore his sense of integrity. Then, pressed by Andrea, he wavers. He realizes, however, that if he capitulates to the IRA, "he would lose for ever something precious ... some secret of his own worth." The "hero" will dwindle into the accomplice, prolonging the lies of silence. Moore ends the novel with an ironic stroke. Before Michael reaches the telephone to inform the police of his decision, the Belfast assassins arrive to do their terminating job. Concentrated in point of view and time, presented through a fairly solidly realized character against a quite sharply realized scene, Lies of Silence somehow disappoints the reader with a sense of flatness. Perhaps it is helpful to look back at an interview Moore gave about 20 years ago. "Ordinariness," he said, "is one of my main concerns in writing." In Michael Dillon, Moore presents a character with whom his readers have become familiar, perhaps too familiar, in the fiction he has written over the last three decades. Perhaps, too, the reality of the Belfast situation, constantly present in the press and more graphically on television, has numbed us: the extraordinary has become too much the accepted ordinary to move us any longer. Despite the professionalism that we have come to expect of Brian Moore, Lies of Silence remains one of his less interesting, less effective works