Stimulating look across a dotted line; Divisions on a Ground: Essays on Canadian Culture, by Northrop Frye. Toronto: House of Anasi Press Ltd. (distributed by University of Toronto Press, 33 East Tupper Street, Buffalo, N.Y., 14203). 199 pp. $19.95.

Canada and the United States share a border, but if truth be told, many Americans know little of their neighbor's culture and concerns and perhaps care less. Northrop Frye, born in Quebec, nurtured in New Brunswick, and professor of literature at the University of Toronto since 1939, is supremely qualified to stimulate Americans' awareness of Canada's distinctiveness.

This short book, divided into three sections, ''Writing,'' ''Teaching,'' and ''The Social Order,'' contains 13 closely written essays on subjects as diverse as Canadian history, the role of the university, the relationship of Canada to both Britain and America, and the legacy of writers such as Marshall McLuhan, Morley Callaghan, and Margaret Atwood.

An American reader may be most attracted to Frye on the subject of the differences between Canadians and Americans, which Frye notes perceptively. Yet first and foremost, Frye is a literary critic, and his essays on the development of Canadian literature reflect a profound concern that Canadian writers not be labeled colonial or provincial, while simultaneously stressing the writer's right and necessity to address a particular locale.

These carefully reasoned essays offer an exercise in expanding awareness -- a kind of ''through the looking-glass'' experience for Americans not too self-centered to venture across a nearby border.