Jack London 
Call of the Wild [PDF ebook] 

The Call of the Wild is Jack London’s most popular book and is considered by many to be his best. Telling the story of Buck, a domesticated dog whose wild instincts begin to kick-in while serving as a sled dog in the treacherous Yukon. The novel’s tone is often dark, and despite being considered juvenile literature by some, it portrays much violence and cruelty. The Call of the Wild was followed in 1906 by White Fang with its mirroring plot of a wild wolf becoming domesticated by a miner.