Ann, Roger and Jack of spend a bewitched summer with old Mrs. Whiton in her fascinating old house south of Boston. The Natterjack -- an enchanted frog with a Cockney accent -- brightens the summer days with his power over time. He transports the children back to Revolutionary days to aid Paul Revere in his endeavors. They counsel monarchs, Queen Elizabeth and Queen Victoria, and assist fugitives in the Underground Railway. The transitions in time may confuse young readers. Deftly handled, with musical comedy dialogue this is by no means every child's cup of tea. But for youngsters who would like a book about magical happenings this is good.