Isaac Asimov's Science Fiction Magazine: April 13, 1981.
Volume 5, Number 4 (whole #38.) Cover by Robert Crawford (for "Unicorn Variation")

Featured stories:
"Unicorn Variation" by Roger Zelazny (novelette - winner of 1982 Hugo award)
"The Stuff Itself" by James Gunn (article)
"False Scent" by Rick Raphael
"The Hotter Flash" by J. O. Jeppson ("Pshrinks Anonymous" series)
"Twitch on the Bull Run" by Sharon Webb (a "Terra Tarkington" story)
"Space and the Longevity of Man" by Stefan T. Possony & Jerry Pournelle (article)
"The House of If" by Barry B. Longyear (novelette.)