Vesper Holly has foiled murderers, crossed mountains, and narrowly escaped earthquakes. Now she's home in Philadelphia, where she can relax-until President Ulysses S. Grant asks for her help. The Centennial Exposition of 1876 is about to begin, and luminaries from around the world will be there. But so will Vesper's arch-nemesis, the evil Doctor Helvetius. There's only one person who can thwart his evil plans-Vesper Holly!
Lloyd Chudley Alexander was an influential American author of more than forty books, mostly fantasy novels for children and adolescents, as well as several adult books. His most famous contribution to the field of children's literature is the fantasy series The Chronicles of Prydain. The concluding book of the series, The High King, was awarded the Newbery Medal in 1969. Alexander's other books have also won the National Book Award and the American Book Award. He was also one of the creators of Cricket Magazine.