Frederik Pohl said in 1965 that Gernsback's Amazing Stories published "the kind of stories Gernsback himself used to write: a sort of animated catalogue of gadgets". Gernsback's fiction includes the novel Ralph 124C 41+; the title is a pun on the phrase "one to foresee for many" ("one plus"). Even though Ralph 124C 41+ has been described as pioneering many ideas and themes found in later SF work, it has often been neglected due to what most critics deem poor artistic quality. Author Brian Aldiss called the story a "tawdry illiterate tale" and a "sorry concoction", while author and editor Lester del Rey called it "simply dreadful." While most other modern critics have little positive to say about the story's writing, Ralph 124C 41+ is considered by science fiction critic Gary Westfahl as "essential text for all studies of science fiction."
Gernsback's second novel, Baron Münchausen's Scientific Adventures, was serialized in Amazing Stories in 1928.
Gernsback's third (and final) novel, Ultimate World, written c. 1958, was not published until 1971. Lester del Rey described it simply as "a bad book", marked more by routine social commentary than by scientific insight or extrapolation. James Blish, in a caustic review, described the novel as "incompetent, pedantic, graceless, incredible, unpopulated and boring" and concluded that its publication "accomplishes nothing but the placing of a blot on the memory of a justly honored man."
Gernsback combined his fiction and science into Everyday Science and Mechanics magazine, serving as the editor in the 1930s.