Book #3: OH,BABY! When Katie turns into her best friend Suzanne's baby sister, Heather, things are bad enough. But when Katie, as Heather, speaks to Suzanne, Suzanne thinks that her baby sister is a genius! How will Katie ever explain to Suzanne that it wasn't really Heather doing the talking, without spilling her big secret?

Book #4: GIRLS DON'T HAVE COOTIES Katie's best friend Jeremy and the other boys from Class 3A have decided that all girls have cooties, but when Katie finds herself in Jeremy's shoes - really - she tries to reunite the boys and the girls. Will Katie's plan work? Or will it just be one huge mess?