Stranger in the Mirror — Allen Say

Overnight, Martin has changed. His parents take him to one doctor after another, only to be told there is nothing wrong with their son. At school, his classmates will not play with him. At home his family tries to treat him as if he were the same child. But things are now different. Martin has grown very old in the space of one day. His world will never be the same again. This haunting story exposes the agony caused by American attitudes towards aging and differences. -- School Library Journal, starred review