IF! was a science fiction fanzine edited by Conrad ("Con") Pederson and published in the late 1940s from Inglewood, California, U.S.A.
IF! lasted at least four issues. The third issue was published in June 1948 and the fourth in October 1948.
The fourth issue included work by Forrest J Ackerman (Imagination!), R. Flavie Carson, Lin Carter (Spaceteer), David H. Keller, Joe Kennedy, Len Moffatt (Shangri L'Affaires). Cover art by was Pederson. Illustrations were by Pederson and Miller.