A lad with multiple sclerosis describes his Service Dog—an unusually intelligent, affectionate golden retriever whose name is Buddy and who not only fetches and carries (he has a backpack marked ``Working Dog—Don't Touch'') but also turns out lights, pushes elevator buttons, showers with his wheelchair-confined master, and does dozens of other tasks at home and at school. A detailed, upbeat picture of happy cooperation between boy and dog, appealingly illustrated with realistic watercolors. (Picture book. 4-10)