Blue Balliett's books are wonderful for tweens, both boys and girls. Chasing Vermeer, The Wright 3, and The Calder Game feature tween protagonists who get drawn into mysterious happenings involving famous works of art and architecture. They are amazingly detailed and clever, and will have readers heading to Wikipedia to look up the works of Vermeer, Frank Lloyd Wright and Alexander Calder, which is wonderful. They are full of codes and deductive thinking, and will have readers seeking out mysteries of their own, or at least composing coded notes to their buddies or buying a set of pentaminoes. These books are highly recommended!