This novel was removed from dictatorships in Europe during the the 1920s and 1930s. From Wikipedia: "The Call of the Wild is a novel by American writer Jack London. The plot concerns a previously domesticated dog named Buck, whose primordial instincts return after a series of events leads to his serving as a sled dog in the Yukon during the 19th-century Klondike Gold Rush, in which sled dogs were bought at generous prices."