Winston Churchill apparently referred to his depression as a 'black dog.' Very evocative. Also, now, the conceit underlying this novel, in which a large, talking black dog turns up on the doorstep of a young widow, insistent upon renting a room from her. Her new lodger trashes the place - which is conveniently located near his job depressing Churchill - and takes increasing liberties as the anniversary of her husband's death approaches. Marvelous conceit, and I like it better as I summarize it, but the characters are flat and the Churchillian dialogue soporific.