Nightshade by Susan Wittig Albert
"Howard Cosell comes in off the porch where he's been lying with his chin on his paws, hoping that Brian might miss the bus and come back home but knowing gloomily that he won't. He looks up at McQuaid, wondering if he can have some burrito, too. A little bit of burrito would go a long way toward easing the pangs of loneliness." Not only is Howard Cosell an absolutely brilliant name for a Basset Hound (!) but what a terrific expression of canine angst - and a life lesson. Pass me a bite of burrito...