MONTREAL`S JOHN BUELL, the author of four novels since his debut in 1959 with The Pyx (later made into a movie), is neither prolific nor widely known, but on the evidence of A Lot to Make Up For (HarperCollins, 202 pages, $19.95 cloth), he deserves a wide readership. This is a subtle and well-paced suspense tale, with carefully observed and skilful manipulation of emotions. Stan Hagen, a recovered alcoholic and drug addict, has set out to find his former girlfriend, Adele, also an ex-addict, who has started a new life for herself and her baby, who was born addicted. With his small-town settings and working-class characters, Buell seems akin to the "dirty realism" of Raymond Carver and Bobbie Ann Mason, but unlike them he is more interested in psychology than sociology. In a funny way he seems closer to the hard- boiled writers of the `50s, such as Jim Thompson, who wrote about down-and-outers with humour, emotion, and, above all, a strong narrative line.