Kline and Burroughs
Kline is best known for an apocryphal literary feud with fellow author Edgar Rice Burroughs, in which he supposedly raised the latter's ire by producing close imitations (The Planet of Peril (1929) and two sequels) of Burroughs's Martian novels, though set on Venus; Burroughs, the story goes, then retaliated by writing his own Venus novels, whereupon Kline responded with an even more direct intrusion on Burroughs's territory by boldly setting two novels on Mars. Kline's jungle adventure stories, reminiscent of Burroughs's  While the two authors did write the works in question, the theory that they did so in contention with each other is supported only circumstantially, by the resemblance and publication dates of the works themselves. The feud theory was originally set forth in a fan press article, "The Kline-Burroughs War," by Donald A. Wollheim (Science Fiction News, November, 1936), and afterward given wider circulation by Sam Moskowitz in his book Explorers of the Infinite (1963). Richard A. Lupoff debunked the case in his book Edgar Rice Burroughs: Master of Adventure (1965). Among the evidence cited by Lupoff discounting the feud: (1) no comment from either writer acknowledging the feud is documented, and (2) family members of the two authors have no recollection of ever hearing them mention it. In response to Lupoff's investigations Moskowitz identified his original source as Wollheim's article, while Wollheim stated, when questioned on the source of his own information: "I made it up!"