Summer of the Re-Read! I read this book back when I was eight or nine and LOVED it.
Claudia decides to run away in order to show her parents what life without her is like. She plans strategically, taking her little brother, Jamie to go with her because he's saved up a lot of money. They run away to the Metropolitan Museum of Art. A statue of an angel is on display and the sculptor of the statue is in question. Claudia is determined to find out who the real sculptor is. That's where the mixed up files of Mrs. Basil E. Frankweiler come in....and what Claudia discovers allows her to go back home to her family.
I was afraid that if I re-read this book, I wouldn't like it as much as I did when I was a little person. However, it was maybe even more charming, clever, and sweet than I had understood back then. I still love this book!