Jack London 
Call of the Wild Level 3 Oxford Bookworms Library [EPUB ebook] 

A level 3 Oxford Bookworms Library graded reader. Retold for Learners of English by Nick Bullard. When men find gold in the frozen north of Canada, they need dogs — big, strong dogs to pull the sledges on the long journeys to and from the gold mines. Buck is stolen from his home in the south and sold as a sledge-dog. He has to learn a new way of life — how to work in harness, how to stay alive in the ice and the snow . . . and how to fight. Because when dog falls down in a fight, he never gets up again.