He published a science fiction poem (Carcajou Lament) in Triquarterly in December 1959, but drifted away from poetry. He has published reviews of SF and other stuff in magazines and papers since 1960, with some continuity: New Worlds from 1966 till it stopped; the Toronto Globe & Mail from 1966/67 to 1998, though with a 31 year break; F&SF from the early 1970s until Ed Ferman got tired of him; the Washington Post from 1980; and Interzone from the beginning. Other publication venues have included (Canada) Varsity, Toronto Star (a weekly NewFiction column), (US) Collage, The New York Times, The Los Angeles Times, Omni, The New York Review of Science Fiction, Science Fiction Weekly, Nova Express, Science Fiction Eye, (UK) Times Literary Supplement, Observer, Sunday Times, Guardian, Independent, Correspondent, Mail on Sunday, New Statesman, New Scientist, Listener, and Foundation.
As a novelist and critic in the literature of the fantastic, there are three central strands to his works: the novels (one in 1977, one in 1999); the encyclopedias from 1975; the criticism, put into volume form in 1988 and 1996. They are the loot of his exile. His titles have included The Aspen Poetry Handbill (1965, editor), The Disinheriting Party (1977), The Encyclopedia of Science Fiction (1979, associate editor), Interzone: the 1st Anthology (1985, co-editor), Interzone: the 2nd Anthology (1987, co-editor), Strokes: Essays and Reviews 1966-1986 (1988), Interzone: the 3rd Anthology (1988, co-editor), Interzone: the 4th Anthology (1989, co-editor), Interzone: the 5th Anthology (1991, co-editor), The Encyclopedia of Science Fiction (1993, co-editor), Science Fiction: The Illustrated Encyclopedia (1995), Look at the Evidence: Essays and Reviews (1996), The Encyclopedia of Fantasy (1997, co-editor), The Book of End Times (1999), and Appleseed (1999).
He is a trustee for the Telluride Institute (Telluride, Colorado, 1986-present) and The Science Fiction Foundation (England, 1997-present). His awards have included Canada Council Short Term Grant (1967), Canada Council Junior Fellowship (1968), Readercon Award (1989), BSFA Special Award (1994, with Nicholls), Eastercon Award (1994, with Nicholls), Locus Award (1994, with Nicholls), Roundtable Award (1994, with Nicholls), Pilgrim Award (1994), Hugo Award (1994, with Nicholls), Eaton Grand Master Award (1995, with Nicholls), Locus Award (1996), Science Fiction Weekly Reader Appreciation Award (1996), Hugo Award (1996), Locus Award (1997), Barry R Levin Collectors Award (1997), Locus Award (1998, with Grant), Mythopoeic Society Award (1998, with Grant), Hugo Award (1998, with Grant), World Fantasy Award (1998, with Grant), Eaton Award (1999, with Grant), and Distinguished Scholar Award (1999, IAFA).