Puberty is troubling, not only to the child facing adulthood but to friends who aren't themselves ready for the change. This is an amusing and affectionate novel about such a situation. Twelve-year-old Kit can't wait for summer to begin so that she and best-friend Phoebe can pick up where they left off last summer. She feels deeply betrayed when her friend comes back from a trip to Paris filled with a new sophistication and maturity. Kit cannot resist revenge, and then must live with herself after it. This is a nicely constructed story, with a pleasant setting on a Martha's Vineyard-like colony that has an active summer theater. There is a nice subplot of Kit trying to convince her little sister to let their grandmother be her true theatrical self. On a literary and emotional level that will be understood and appreciated by middle-graders, this has considerable humor to keep it from being a book ""with a lesson."" Good for both school and public library collections.