if, subtitled "Worlds of Science Fiction", was launched in March 1952, the creation of James L. Quinn of the Quinn Publishing Company, not to be confused with Robert Guin, who later published both if and its sister magazines including Galaxy (the title If had previously been used by Con Perderson in 1948 for a science fiction fanzine).

The original cover bore a distinctive if in oversized lower-case letters, with a line across the top of the logo reading "Worlds of Science Fiction" with a rectangle that enclosed most of the large "if" letters and the words "Worlds of," which from the beginning suggested the title could be read as "Worlds of if". In 1972 Worlds of if was made the official name of the magazine, so that issues after 1972 are sometimes indexed separately.



The editoral succession at if seems to have been as follows

Paul W. Fairman: March 1952–September 1952

James L. Quinn: November 52–August 1958 (for a significant portion of this period, Larry T. Shaw served as Associate Editor, wrote the editorials and generally did most of the editorial duties. He also briefly employed writer Lee Hoffman as his assistant; they later wed.)

Damon Knight: October 1958–February 1959

H.L. Gold: July 1959–November 1961 (Gold was ill for part of this period, and some issues listing him as editor were actually edited by Fred Pohl.)

Frederik Pohl, January 1962–May 1969

Ejler Jakobsson: October 1969–January/February 1974

Jim Baen: March/April 1974–December 1974 (if ceased publication and was incorporated into Galaxy.)

Clifford R. Hong: Fall (September/November) 1986. This attempt to revive if as a quarterly lasted only one issue.