Kline is best known for his purported novelistic feud with Edgar Rice Burroughs. In 1929, long before planetary romance became a conventional genre, he wrote Planet of Peril, a novel set on the planet Venus and written in the storytelling form of Burroughs's Martian novels. He followed this with two sequels. In response to Kline's "poaching" on his territory, Burroughs began writing his own Venus series. Kline's rejoinder was an even more direct intrusion, boldly setting two novels on Mars. He also wrote of white jungle adventurerers quite reminiscent of Burroughs's Tarzan. However, the evidence of the feud itself is indirect, and the feud was not proposed to have existed until after both writers were dead. No comment from either writer acknowledging the feud is documented. Whether or not the feud actually existed or is merely a literary theory concocted after the fact is unknown.
In the mid-1930s Kline largely abandoned writing to concentrate on his career as a literary agent (most famously for fellow Weird Tales author Robert E. Howard, pioneer sword and sorcery writer and creator of Conan the Barbarian). Kline represented Howard from the Spring of 1933 till Howard's death in June 1936, and continued to act as literary agent for Howard's estate thereafter. It has been suggested that Kline may have completed Howard's "planetary romance" Almuric, which he submitted to Weird Tales for posthumous publication in 1939, although this claim is disputed.
Novels
Maza of the Moon (1929)
Tam, Son of the Tiger (1931)
Jan of the Jungle (1931)
Jan in India (1935)
Call of the Savage (1937)
The Dragoman's Revenge (2007)
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