T-BACKS, T-SHIRTS, COAT, AND SUIT

When Zack, manager of a fleet of lunch vans, urges his crew to wear T-backs ("a bathing suit that covered as little as it left to the imagination"), Chloa's aunt Bernadette is the one holdout. Chloa, 12, is in Florida for the summer; she's promised her stepdad to help his sister and to "give the unexpected a chance." Construction crews flock to the vans staffed by the shapely conformists; Bernadette's profits fall, and she's demoted to a still less lucrative spot. Meanwhile, Chloâ helps out, and mischievously tries to convince the mildly obnoxious 13-year-old son of one of the T-back wearers that her aunt is a witch; and a right-wing religious group organizes "Citizens Opposing All T- backs" ("COAT"). The plot thickens (rather implausibly) when COAT, failing to enlist Bernadette, demands that she defend herself against their charge of witchcraft. But admirers of Konigsburg won't be surprised to find that that's no more the crux of her novel than the indecent clothing issue. In the end, what Bernadette successfully defends is her right to choose, without explaining. She and Chloa also establish a warm relationship, of value to both, while Chloa learns (like Claudia in From the Mixed-Up Files...) that she's responsible for her own identity. The author's forthright, staccato style and witty descriptions are marvelous; occasional interpolated anecdotes (e.g., a succinct thriller about how Bernadette got her dog; lively precis of Savonarola and Galileo) amplify the theme and characterizations. Offbeat, comic, thought-provoking: a top-notch author at full strength. (Fiction. 9-13)