Interior illustration by Edd Cartier
for L. Ron Hubbard's Fear
, in Unknown
, May 1940
In early 1940, Farnsworth Wright was replaced as editor of Weird Tales by Dorothy McIlwraith, who also edited Short Stories. McIlwraith had no particular expertise in the horror field and, although she was a competent editor, the Wright era is generally considered to have been Weird Tales heyday. With Wright's departure, Unknown quickly became the leading magazine in its small field. Unknown acquired a stable of regular writers, many of whom were also appearing in Astounding, and all of whom were comfortable with the rigor that Campbell demanded even of a fantasy plot. Frequent contributors included L. Ron Hubbard, Theodore Sturgeon, and L. Sprague de Camp, who, in collaboration with Fletcher Pratt, contributed three stories about a world where magic operates by logical rules. The stories were later collected as part of Pratt and de Camp's "Incompleat Enchanter" series; John Clute has commented that the title of one of them, "The Mathematics of Magic", is "perfectly expressive of the terms under which magic found easy mention in Unknown". Other stories still regarded as classics include "They" by Heinlein, "Smoke Ghost" by Fritz Leiber, along with several stories in Leiber's Fafhrd and the Gray Mouser series, and "Trouble With Water" by H.L. Gold. Unknown's influence was far-reaching; according to Ashley, the magazine created the modern genre of fantasy, and science fiction scholar Thomas Clareson suggests that by destroying the genre boundaries between sf and fantasy it allowed stories such as Simak's City series to be written. Clareson also proposes that Galaxy Science Fiction and The Magazine of Fantasy & Science Fiction, two of the most important and successful science fiction and fantasy magazines, were direct descendants of Unknown.
In 1941 Weisinger left Standard Magazines to work on the early DC Superman comics, and Oscar J. Friend took over as editor of Startling, Thrilling Wonder, and Captain Future; Strange Stories, which had been Weisinger's idea, was killed off with the January issue. Friend continued the juvenile focus of the three sf magazines, and the covers, often by Earle K. Bergey, reinforced the editorial policy: they frequently included women in implausibly revealing spacesuits or wearing Bergey's trademark "brass brassières". Captain Future ceased publication in early 1944, and later that year Friend was replaced as editor by Sam Merwin on both Startling and Thrilling. Planet Stories' first few issues contained little notable fiction, but it improved throughout the war. Leigh Brackett was a regular contributor of planetary romances—melodramatic tales of action and adventure on alien planets and in interplanetary space—and her work had a strong influence on other writers, including Marion Zimmer Bradley. Other well-known writers who sold to Planet included Simak, Blish, Fredric Brown, and Asimov.
June 1943 issue of Startling Stories
; cover by Earle K. Bergey, showing his trademark "brass bra"
At Ziff-Davis, Palmer remained editor of both Fantastic Adventures and Amazing Stories throughout World War II. Much of the material in both magazines came from a group of Chicago-based writers who published under both their own names and various house pseudonyms; among the most prolific were William P. McGivern, David Wright O'Brien,
Don Wilcox, and
Chester S. Geier. The fiction was rarely noteworthy; Ashley describes the wartime Fantastic Adventures as "concentrat[ing] more on quantity than quality, on brash sensationalism than subtlety", though he also comments that it was the most attractive science fiction or fantasy magazine on newsstands at the time, with covers by J. Allen St. John, Harold McCauley, and
Robert Gibson Smith. Similarly, the fiction in Amazing was of uneven quality, though occasionally Palmer obtained good material, including stories by Ray Bradbury, Eric Frank Russell, and John Wyndham.
Few of the new magazines launched during the boom lasted until the end of the war, which brought paper shortages that forced difficult decisions on the publishers. Not every magazine cancellation was because of the war; the usual vicissitudes of magazine publishing also played a role. In 1941, Silberkleit cancelled Science Fiction after 12 issues because of poor sales, merging it with Future Fiction. Two years later Silberkleit ceased publication of both Future and Science Fiction Quarterly when he decided to use the limited paper he could acquire for his western and detective titles instead. Both Science Fiction and Future eventually reappeared in the 1950s. Fantastic Novels merged with its stablemate, Famous Fantastic Mysteries, in 1941, probably because of wartime difficulties, after only five issues. In 1942 Famous Fantastic Mysteries was sold by Munsey to Popular, who were already the publishers of Astonishing Stories and Super Science Stories. Mary Gnaedinger continued as editor, but the editorial policy changed to exclude reprints of stories that had appeared in magazine form. Booklength work was still reprinted, including G. K. Chesterton's The Man Who Was Thursday and H. G. Wells' The Island of Dr. Moreau. In the event, Famous Fantastic Mysteries was the only one of Popular's science fiction and fantasy titles to survive the war. Both Astonishing and Super Science Stories ceased publication in 1943 when Frederik Pohl, the editor of both titles, enlisted in the army; the publisher was having difficulty obtaining enough paper and decided to close the magazines down. The same year, paper shortages forced John Campbell to choose between Astounding and Unknown, which had already gone to a bimonthly schedule; he decided to keep Astounding on a monthly schedule, and Unknown ceased publication with the October 1943 issue. Astounding switched to digest format the following month; this was a leading indicator for the direction the field would take, though it would be over a decade before the rest of the field followed suit.