One of Newbery Honor author Avi's most popular middle-grade mysteries is available in paper once again. The mystery revolves around a rare edition of The Wizard of Oz missing from the local library. When Becky is accused of stealing it, she and her twin brother Toby set out to catch the real thief and prove her innocence. Clues cleverly hidden in four other books lead to a hidden treasure--and a gripping adventure.