Swordsmen In The Sky
by Donald A. Wollheim
Cover code F-311 indicates first of two printings. Collects five stories: Swordsmen of Lost Terra (1951) by Poul Anderson; The People of the Crater (1947) by Andre Norton; The Moon That Vanished (1948) by Leigh Brackett; A Vision of Venus (1933) by Otis Adelbert Kline; and Kaldar, World of Antares (1933) by Edmond Hamilton. Wonderful space opera!