Chasing Vermeer, by Blue Balliett, 2006.

What do frogs, twelves, used books, anonymous letters, pentominoes, old lady neighbours, and stolen paintings have in common? Who knows! Ms. Hussey, Petra and Calder’s sixth grade teacher, says asking questions can be dangerous. But when a priceless Vermeer painting turns up missing – the very same painting Petra had dreamed about a few days before – Petra and Calder have lots of questions to ask. Middle-grade history-mystery, recommended.