Mainstream was a science fiction fanzine by Suzanne Tompkins and Jerry Kaufman.
Previously, Suzle and Jerry had published The Spanish Inquisition in the 1970s. Mainstream was their return to fanzine publishing in the 1980s from their new location in Seattle, Washington, U.S.A.
Contributing artists included Brad Foster, Jay Kinney (Nope!), Jeanne Gomoll (Janus, Six Shooter), Tim Hammell, Ken Macklin, Teddy Harvia, Joe Pearson, Bill Rotsler, Stu Shiffman, Craig Smith, Dan Steffan (Boonfark), Steve Stiles, Arthur Thomson (The ATom Anthology), David Vereschagin (The Monthly Monthly, Neology), and Taral Wayne (DNQ).
Contributors of writing included Doug Barbour, Gregory Benford (Void), John Berry (Pot Pourri, The Damned Patrol), David Bratman, Ginjer Buchanan, Eli Cohen (Kratophany), Dick Ellington (Metrofan, The Bosses' Songbook), David Emerson (Rune), Gary Farber, Terry Gary, Jeanne Gomoll, Patrick Nielson Hayden (Izzard), Andrew Hooper (Science Fiction Five Yearly), Richard Labonte (Hugin and Munin), Dave Langford (Ansible), R.A. MacAvoy, Loren MacGregor, Sandra Meisel, Jessica Amanda Salmonson (Windhaven), Bob Shaw, Stu Shiffman, Jon Singer, Ted White (Void), Tom Whitmore, and Art Widner (YHOS).
The article "Mozart on Morphine" by Greg Benford was selected for reprinting in the anthology Fanthology '87.
After Mainstream came to an end, Suzle and Jerry would return to publishing a fanzine in the 2000s, with Littlebrook.