Asimov also created a number of alien creatures to populate his Venusian ocean, and this was "not" a common theme of his. Asimov's works usually centered on the interactions of sentient beings, usually humans or robots, or occasionally intelligent aliens, with his fictional worlds serving only as backdrops. For "Oceans of Venus", his only novel-length work set on that world, he hearkened back to the works of Stanley G. Weinbaum, whose imaginative alien ecologies made him a major figure in the science fiction field during his brief writing career in the mid-1930s. In his anthology "Before the Golden Age", Asimov wrote that "Oceans of Venus" was "a conscious imitation of the spirit" of Weinbaum's 1935 story "Parasite Planet", which was also set on Venus.