Bored with her life, twelve-year-old Claudia Kincaid is ready for a big change. In fact, she wants to run away from home. But she doesn't like discomfort. She doesn't even like picnics. So an old-fashioned, knapsack kind of running away is out of the question. Instead of running from somewhere, she decides to run to somewhere - some place comfortable, and preferably beautiful. Where else, but the Metropolitan Museum of Art in New York City? Fare on the train from the suburbs takes three weeks of skipping hot fudge sundaes. Taking Jamie, the second youngest of her three brothers - the quiet one with the largest cache of money - with her, Claudia's life is immediately changed in a big way. Nights she and Jamie take baths in one of the museum's fountains and they sleep in royal beds in the museum's collection, despite the "Please do not step on the platform" sign. Every day they check out by 4:30 and reenter the museum around the back at 5:30. To remain inconspicuous, Claudia and Jamie join school-group tours by day, and when the museum closes, stand on the toilets in the bathroom stalls out of view from the guards checking for strays.

But she and Jamie's vacation from their "real" life turns into an adventure when Angel, a sculpture rumored to have been carved by Michelangelo, arrives. Will they solve a mystery that even the experts can't solve?

Author Konigsburg's tale of a young girl's escape into a search for identity - her own and Angel's - in one of the world's greatest museums was awarded a 1967 Newbery Medal, as well as named an American Library Association Notable Book, and "Best of the Best" by the School Library Journal. Illustrated by Konigsburg's own expressionistic line drawings, the book remains a modern classic.