GIVEN the popular appetite for tales of murder and mystery, publication of yet another collection may be justified; but titling it Great Canadian Murder and Mystery Stories (Quarry, 240 pages, $18.95 paper) is not.

I mean, when a collection comes about because its editors (Don Bailey and Dale Unruh) advertised for submission.,;, then selected two dozen stories from the 263 received, can the results even begin to fit any responsible definition of "great"? Bailey's prefatory remarks indicate that the selection criteria included "a strong sense of the environment where the story took place," characters whose commitment is to "a form of morality that ... [is] ... neither black nor white" but "in the gray shadows," and "the vicarious thrill of participating in the unknown." With such an elastic net, it's not surprising that he and Unruh have caught some peculiar fish. A few of the stories, notably James Bacque's "Desire & Knowledge in Key West," David Helwig's "Red Barn, Interior," Gail Helgason's "Wild Stock," and Helen J. Rosta's "Feathers," are outstanding for their skill with that "vicarious thrill." Others, such as "The Shanghai Noodle Killing" by Ted Plantos, "The Little Black Knife" by Scott Mackay, and "Becoming" by Jake MacDonald, strike a satisfying note of irony. But some of the remaining stories leave too much to the reader's imagination, or gamely reach for effects that they don't quite grasp. Great Canadian Murder and Mystery Stories is such a magpie's nest of a collection, how ever, that what turns one reader off may turn the next reader on.