On the nonfiction shelf there are many to choose from. I had a blast researching Sniffer Dogs and I know many of my fellow writers have also enjoyed meeting so many extraordinary canines. Check out Nancy Furstinger's Paws of Courage and her biography of Henry Bergh. Both are well researched and engaging reads.
Of course, there are also the dog titles that tug on your heartstrings and are better read with a box of tissues.