(YA) Following in the wake of Rascal and sporting some of the same appeal of sentiment, Goodbye Kate introduces a new animal heroine. Kate is a homeless mule that young Isaac finds wandering about the Kentucky hills one summer. Isaac, his father and Author Clark (and Putnam's, too) have much sly fun pretending that Kate ""a thinking mule"" but, as the reader quickly learns, Kate's ""thinking"" is mainly ascribed to her by her new owner, Isaac (she does not literally think, as do several talking equines of movies and TV.) Kate does some pleasantly improbable things, such as walk on logs, react to the word ""corn"" and jump fences rather than kick them down. Her perspicacity becomes the object of several bets, during the outcome of which she shines with canniness. Kate gets thrown in jail for vandalism, put on trial and Isaac defends her. At the end she comports herself heroically during a flash flood and is put out to pasture for her last days. Kate dies with her head in Isaac's lap. The incidents are clever but Isaac is a bit too well scrubbed behind the ears. Another boy with pet is up for reader adoption.