An uncertainty, possibility, condition, doubt etc.
Supposing that, assuming that, in the circumstances that;
In the event that a statement is true (a programming statement that acts in a similar manner).
Even if; even in the circumstances that.
If was an American science fiction magazine launched in March 1952 by Quinn Publications, owned by James L. Quinn. Quinn hired Paul W. Fairman to be the first editor, but early circulation figures were disappointing, and Quinn fired Fairman after only three issues. Quinn then took over the editorial position himself. He stayed in that role until late 1958, though Larry T. Shaw took over most editorial duties for a year from mid-1953. In 1958 Damon Knight was hired as editor, but within three issues Quinn sold the magazine to Robert Guinn at Galaxy Publishing. The new editor at Galaxy Publishing was Horace L. Gold, who was also editing Galaxy Science Fiction. After two years Frederik Pohl took over as editor, and it was under Pohl that If achieved its greatest success, winning the Hugo Award for best professional magazine three years running from 1966 to 1968. In 1969 Guinn sold all his magazines to Universal Publishing and Distribution. Pohl decided not to continue as editor as he wanted to return to his writing career. Ejler Jakobsson became editor; the magazine was not successful under his management and circulation plummeted. In early 1974 Jim Baen took over from Jakobsson as editor, but increasing paper costs meant that UPD could no longer afford to publish both Galaxy and If. Galaxy was regarded as the senior of the two magazines, so If was merged into Galaxy after the December 1974 issue, its 175th issue overall. A semi-professional magazine named If appeared in 1986, intended as a revival of the original, but it folded after a single issue.