Campbell's fantasy magazine, "Unknown", was suited to de Camp's idosyncratic imagination, logic, and sense of humor. He contributed ten novels (five as collaborations), much of it characterized by humor and dry wit. De Camp eschewed the intention of being a satirist, insisting, instead, that the stories he wrote were meant less for instruction or improvement, as satire requires, and more for the amusement of his readers. De Camp's treatment of time travel and alternate history in stories such as "Lest Darkness Fall" (1939), "The Wheels of If" (1940), "A Gun for Dinosaur" (1956), "Aristotle and the Gun" (1958), and "The Glory That Was" (1960) challenged the popular notion of his time that history consisted of an arbitrary series of accidents. Instead, de Camp, through sound background knowledge and logical thought, systematically demonstrated how technological advances could determine the pattern of an eventful history. His display of technological determinism in historical recreation is considered a "tour de force.""Lest Darkness Fall", "The Wheels of If" and "Aristotle and the Gun" have been recognized as seminal works in the field of alternate history. His most extended work was his ""Viagens Interplanetarias"" series, set in a future where Brazil is the dominant power, particularly a sub-series of sword and planet novels set on the planet Krishna, beginning with "The Queen of Zamba". His most influential "Viagens" novel was the non-Krishna work "Rogue Queen", a tale of a hive society undermined by interstellar contact, which was one of the earliest science fiction novels to deal with sexual themes. De Camp wrote a number of lesser-known but nonetheless significant works that explored such topics as racism, which he considered to be more accurately described as ethnocentrism. He pointed out that no scholar comparing the merits of various ethnicities has ever sought to prove that his own ethnicity was inferior to others. De Camp was best known for his light fantasy, particularly two series written in collaboration with Pratt, the Harold Shea stories (from 1940 et seq.) and Gavagan's Bar (from 1950). Floyd C. Gale in 1961 said that they "were far and away the finest team of fantasy collaborators". De Camp and Pratt also wrote some stand-alone novels similar in tone to the Harold Shea stories, of which the most highly regarded is "Land of Unreason" (1942), and de Camp wrote a few more of this genre on his own.