At the end of From the Mixed-Up Files of Mrs. Basil E. Frankweiler, a museum guard reports that a violin case and a trumpet case, containing gray-washed underwear and a transistor radio, have been found in the Metropolitan Museum of Art’s lost and found. “No one has claimed them yet.”Yet...

From the Mixed-Up Files of Mrs. Basil E. Frankweiler by E. L. Konigsburg162 pp.     Atheneum     1967     $3.95If there were such a thing as a recipe for a successful children’s book — for which we can be grateful there is not — this one would doubtless violate all the rules. The...