Friend Jane is busy with her big sister and friend Betsy with her little brother, dog Snoopy doesn't want to play, and so Anna makes a sister ""just my size"" out of old tights, T-shirt, and rags. The sister isn't much fun though--""Don't just sit there with that silly grin. Think, you great big dummy!""--so Anna calls her two friends back, and now they are both free to come over and see the new sister. The story is presented as a monologue in Anna's words--for which Hoban's illustrations, with their bare minimum of background or detail, serve as a soft spotlight. Not dumb, but no great big deal either.