genre of fantasy, though commercial success for the genre had to wait until the 1970s. Clareson also suggests that Unknown influenced the science fiction that appeared in Astounding after Unknown folded. According to this view, stories such as Clifford Simak's City series would not have appeared without the destruction of genre boundaries that Campbell oversaw. Clareson further 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. Unknown is widely regarded as the finest fantasy magazine ever published: Ashley says, for example, that "Unknown published without doubt the greatest collection of fantasy stories produced in one magazine." Despite its lack of commercial success, Unknown is the most lamented of all science fiction and fantasy magazines; Lester del Rey describes it as having gained "a devotion from its readers that no other magazine can match". Edwards comments that Unknown "appeared during Campbell's peak years as an editor; its reputation may stand as high as it does partly because it died while still at its best". Bibliographic details Unknown was edited by John W. Campbell and published by Street & Smith Publications throughout its run. It was pulp-sized from its launch through August 1941, and then bedsheet-sized from October 1941 to April 1943. The last three issues were pulp-sized again. Street & Smith had planned to switch it to digest size with the December 1943 issue, but it was canceled before that issue appeared. The price began at 20 cents and rose to 25 cents with the change to bedsheet size; it remained at 25 cents when the size changed back to pulp. It had 164 pages when pulp-sized and 130 pages while it was bedsheet-sized. It began as a monthly and switched to bimonthly from December 1940 on. The volume numbering was regular, with six volumes of six numbers and a final volume of three numbers. The title began as simply Unknown. In December 1940 "Fantasy Fiction" was added as a subtitle, and from the October 1941 issue the title became Unknown Worlds. The first six U.S. issues were available directly in the UK, but thereafter an abridged British reprint edition was issued by Atlas Publications, beginning in September 1939. It was pulp-sized, and priced at 9d (nine pence) throughout. It appeared on a regular monthly schedule until December 1940, after