Claudia and the Genius of Elm Street — Ann M. Martin

Little Rosie Wilder is perfect at everything. She can sing and dance, she plays several musical instruments, and her I.Q. is so high, it's off the scale.

So how did Claudia "C -- " Kishi get stuck baby-sitting for Rosie the genius? Because Rosie is so obnoxious, no one gets along with her -- not even Claudia's sister, who's a genius, too.

The Baby-sitters think that Rosie needs to be taught a good lesson. But what Rosie really needs is a good friend... like Claudia.