<P> A new exhibit draws sensational crowds and fascinates the children: the marble statue of an angel, the sculptor unknown but suspected to be Michelangelo . It was purchased at auction, for only a few hundred dollars, from Mrs. Basil E. Frankweiler, a collector who recently closed her showcase Manhattan residence . The children research it on site and at the Donnell Library, and give their conclusion to the museum staff anonymously . </P> <P> After learning they have been naive, the children spend the last of their money on travel to Mrs. Basil E. Frankweiler's home in Connecticut . She recognizes them as runaways but sets them briefly to the task of researching the angel from files in her long bank of cabinets . Despite the idiosyncratic organization of her files, they do discover the angel's secret--Mrs. Frankweiler has purposefully "given away" a virtually priceless Michelangelo to the Met . In exchange for a full account of their adventure, she will leave the crucial file to them in her will, and send them home in her Rolls - Royce . Claudia learns her deep motive for persisting in the crazy search: she wanted a secret of her own to treasure and keep . Mrs. Frankweiler may get "grandchildren" who delight her . Her lawyer gets a luncheon date at the Met, to revise her will . </P> <P> The Kincaids live in Greenwich, Connecticut . Mrs. Frankweiler lives on a "country estate" in Farmington, Connecticut, closer to Hartford . </P> <Ul> <Li> Claudia Kincaid, 12, is the oldest of four children and the only girl, so she both sets the table and empties the dishwasher . She is a straight - A sixth grade student, a critic of English grammar, and a good planner, except about money which she spends largely on sweets . She feels unappreciated at home, plans to run away with her brother Jamie, and recruits him . They run to the Metropolitan Museum and there discover a mystery of the art world, which fascinates her and overwhelms the adventure . </Li> <Li> Jamie Kincaid, 9, is the third child and the middle boy, in fourth grade, quiet and frugal . He complements his sister perfectly: "adventurous (about everything but money) and rich"--from their viewpoint, an American suburb in the mid ‐ 1960s . He cheats at the card game War, playing with his best friend for money on the school bus daily . From that and his weekly allowance he has saved $24.43, and he has a transistor radio, his one purchase . </Li> <Li> Mrs. Basil E. Frankweiler, 82, is smart, insightful, eccentric, and rich . She is the narrator, telling the story of Claudia and Jamie Kincaid to her attorney . She is a commentator, providing insight into the children's actions . She is plot facilitator, for her election to allow sale of an extraordinary sculpture at auction, for only $225, set the book's mystery in motion . </Li> <Li> Saxonberg is Mrs. Frankweiler's lawyer, and is revealed to be Claudia and Jamie's grandfather . </Li> </Ul>

What is the book from the mixed up files of mrs basil e frankweiler about