Toby, a faithful and affectionate golden retriever, is 14; he's dim of eye, deaf, and smelly, but still his family loyally forgives him everything—all except Sara, whose only apparent response to Toby's infirmities is anger. Her younger brothers, who coax Toby into one more ball game or take him for a walk in a baby carriage, are mystified by Sara's rejection of their beloved old dog. Mom explains that Sara really does still love Toby, but- -with junior high looming—``...doesn't want anything else to change.'' After the vet confirms that the dog is in pain and ``He can't get better. It would be kindest to put him to sleep,'' the two grieving boys creep downstairs to spend Toby's last night with him, only to find that Sara has preceded them. Wild describes the realistic events with touching simplicity. Young's beautifully observed watercolors are less impressionistic than Shirley Hughes's, and include more literal details, but they are in the same richly empathetic spirit. (Picture book. 4-8)