D. Naish, who concluded trends in the data of reported sightings appear to support his hypothesis. Body of work De Camp was a materialist who wrote works examining society, history, technology and myth. He published numerous short stories, novels, non-fiction works and poems during his long career. De Camp had the mind of an educator, and a common theme in many of his works is a corrective impulse regarding similar previous works by other authors. A highly rational and logical thinker, he was frequently disturbed by what he regarded as logical lapses and absurdities in others' writings. Some, like Asimov, felt de Camp's conscientiousness about facts limited the scope of his stories: de Camp was reluctant to use technological or scientific concepts (e.g., hyperspace or faster-than-light travel) if he did not think them possible. Thus, his response to Mark Twain's A Connecticut Yankee in King Arthur's Court was to write a similar time travel novel (Lest Darkness Fall) in which the method of time travel was rationalized and the hero's technical expertise both set at a believable level and constrained by the technological limitations of the age. In like fashion, he reimagined space opera and planetary romance in his "Viagens Interplanetarias" series, and the prehistoric precursor civilizations characteristic of much heroic fantasy in his Pusadian series. When he was not debunking literary conventions he was often explaining them. For example, in the Harold Shea stories co-written with his longtime friend Fletcher Pratt (1897–1956), the magical premises of some bodies of myths and legends were accepted but examined and elucidated in terms of their own systems of inherent logic. The imaginative civilizations in The Compleat Enchanter, for example, are built upon a cultural and technological reality based on scientific formulas. Characters may be transported to these different worlds, but the magic contained within those worlds is only feasible to the extent that it coincides with the technology of the day (e.g., the combustion engine). De Camp's explanatory tendency also carried over into his non-fictional writings, including advice to science fiction writers on handling the different states of languages in future worlds. Science fiction De Camp's science fiction is marked by his interests in linguistics, ancient history, and the history and philosophy of science. His first published story was "The Isolinguals", in the September 1937 issue of Astounding Science Fiction—the last issue edited by F. Orlin Tremaine, prior to the long tenure