Agree w/ a prior reviewer - this book was VERY disappointing. I was horrified to hear it read, for the first time, by a 'teacher' (who obligingly filled in the dialogue for the non-mouse animals, to say to the mouse: "No I don't want to be your friend. . . your too little (or whatever)."
I think it can be read w/ a more positive spin, e.g., "I'd love to be your friend, but I can't play right now. . . " But the illustrations really convey a negative message to kids, and on its face is about being friends w/ your own kind, since it's only the mouse at the end who says "Yes." Not what I want to teach to my children. This book apparently was written in the 70's. It's way out of date, and I wouldn't buy it. Other Carle books have the same type of animal illustrations, so it's nothing special in that regard either.