Mixed Up Files
by E. L. Konigsburg
Claudia and her brother Jamie run away from home to live in the Metropolitan Museum of Art in New York City, where they become involved in solving the mystery of a statue that might have been created by Michelangelo.
4th GradeNovels
About E. L. Konigsburg
Elaine Lobl Konigsburg was an American writer and illustrator of children's books and young adult fiction. She is one of seven writers to win two Newbery Medals, the venerable American Library Association award for the year's "most distinguished contribution to American children's literature, and the only author to win the medal and receive an honor in the same year"
via WikipediaISBN: 9780689711817