Rollo, a medium-sized piebald mix-breed, was Jack London’s playful childhood companion, and taught him that dogs feel “instinct, sensation, and emotion, and are capable of simple reasoning.” In his essay “The Other Animals”, London credits Rollo with inspiring him to look deeper for the possibilities in dogs, and helped form the basis for his classics Call of the Wild and White Fang. Those two books, featuring canine protagonists that demonstrated reasoning, felt emotions, and acted on loyalties, have inspired generations of dog lovers (including this writer) to include dogs in their lives. Jack London lived 1876-1916.
The Dog Guy 
I have been surprised at how many folks are concerned about London’s thoughts about dogs. Jack London was born just ten years after the American Civil War. That his views are relatively antiquated is normal; exceptional is how advanced he was for the time in which he lived.