US pulp Magazine, 39 issues, March 1939-October 1943, monthly until December 1940, then bimonthly, retitled Unknown Worlds from October 1941, published by Street & Smith, New York; ed John W Campbell Jr (1910-1971).
Along with Weird Tales, this was one of the most influential of all fantasy magazines, and in content superior to its rival. U published more quality fantasy per issue than any other magazine, and reawakened public interest about the genre. Legend has it that the magazine was launched in order to publish Sinister Barrier (1939; 1943; rev 1948) by Eric Frank Russell (1905-1978), but in fact Campbell had for a while considered the need for a magazine to cater for the good stories he was receiving at Astounding Science-Fiction which were insufficiently technocentric for his purposes. As with Astounding, he endeavoured to establish a core of writers for U; his two major contributors became L Ron Hubbard and L Sprague de Camp. Hubbard produced 14 stories, of which eight were lead novels, including his classic Psychological Thriller Fear (1940; 1957). Whereas Hubbard usually cast his protagonists into Dream worlds of their own making, de Camp and Fletcher Pratt – starting with "The Roaring Trumpet" (1940), later assembled with "The Mathematics of Magic" (1940) as The Incomplete Enchanter (fixup 1947) – sent their hero Harold Shea into Alternate Worlds based on different national Mythologies. In de Camp's and Pratt's worlds the fantasies were based on some external logic, whereas in Hubbard's they relied solely on internal logic.
Either way, Campbell sought to ensure the fantasy elements in U obeyed some set of laws, in effect treating the supernatural as another science (> Rationalized Fantasy). He worked with Robert A Heinlein to produce the extreme example of this in "The Devil Makes the Law" (1940; vt "Magic, Inc." in Waldo and Magic, Inc. coll 1950), in which Magic is an inextricable part of life's bureaucracy. When Jack Williamson produced a Werewolf story, Darker Than You Think (1940; exp 1948) he treated the subject scientifically, introducing a new evolutionary strain of humanity. The same attention to logic and law was made by Fritz Leiber in his tale of modern Witchcraft, Conjure Wife (1943; 1953).
Some of the classic shorter fiction published in U included: "Trouble With Water" (1939) by H L Gold; "The Cloak" (1939), a modern Vampire story by Robert Bloch; "Two Sought Adventure" (1939) by Leiber, his first appearance in print and the start of the Fafhrd and Gray Mouser series; "When It was Moonlight" (1940) by Manly Wade Wellman, a Recursive Fantasy featuring Edgar Allan Poe; "It" (1940) and "Yesterday was Monday" (1941), the latter a humorous Wainscot story (U's stories were full of wainscots involving imps, gnomes, etc.), both by Theodore Sturgeon; "They" (1941) by Heinlein; and "Smoke Ghost" (1941) by Leiber, arguably the first seriously modern Ghost Story. There were many other excellent stories by Robert Arthur, Nelson S Bond, Anthony Boucher, Fredric Brown, Cleve Cartmill (1908-1964), Lester del Rey (1915- ), Henry Kuttner, Frank Belknap Long, P Schuyler Miller (1912-1974), Jane Rice and A E van Vogt.
U acquired for fantasy a respectability that all but its most exalted forms – e.g., the works of James Branch Cabell, Lord Dunsany and Thorne Smith – had hitherto lacked, and by treating it seriously gave it a new credibility. U established for some writers (especially de Camp and Hubbard) a milieu in which to shine, and boosted the careers of some writers (such as Leiber) who might otherwise have been relegated to lesser markets. It was through U that a commercial genre of fantasy was created, though it would be another 20 years before it established itself in the market.
U had to be sacrificed during WWII to ensure adequate paper supplies for Astounding. Interestingly, the UK reprint (abridged) edition of U rationed the material for longer and survived September 1939-Winter 1949 (41 issues). Plans to reissue U after WWII were aborted, although a retrospective Anthology, From Unknown Worlds (anth 1948; cut 1952 UK) ed Campbell, was issued to test the market. Further anthologies based on the magazine are The Unknown (anth 1963) ed D R Bensen (1927- ) and The Unknown Five (anth 1964) ed Bensen, Hell Hath Fury (anth 1963) ed George Hay (1922-1997), Unknown (anth 1988) ed Stanley Schmidt (1944- ), and Unknown Worlds: Tales from Beyond (anth 1988) ed Schmidt and Martin H Greenberg. [MA]
further reading: The Annotated Guide to Unknown & Unknown Worlds (1991) by Stefan Dziemianowicz.