WHY is Michael Ondaatje a star in CanLit circles, while Rienzi Crusz, a fellow Sri Lankan-born poet, is relatively unknown? Why does the work of many immigrant writers remain marginalized, confined to small presses and critical neglect or dismissal? In Towards an Aesthetic of Opposition (Williams-Wallace, 108 pages, $14.95 paper), a collection of nine essays, Arun Mukherjee argues that it's mainly a matter of who sets the standards: "Literary appreciation, as well as literary production, is culture based and no universal criteria can be worked out that will apply regardless of cultural differences." This is a contentious book, consisting of what Mukherjee calls "oppositional critiques" of works mostly from South Asian writers in Canada and some Third World authors. It is also, I think, an important book, because it raises questions that relate to the issues of voice and minority writers' access to publication, both of which have sparked much debate in the Canadian literary community. A troubling point, though: shouldn't "opposition" be not an end in itself but a step along the road toward making the mainstream more tolerant of difference?