Nine to twelve is not too young for the craving for mystery stories to show itself, so start them with worthwhile ones. The ""Ellery Queen, Jr."" mysteries fill this bill. Djuna, a character in his adult stories, first appeared as the lead character in The Black Dog Mystery. Now he appears again with his Scottle, Champ, and a new friend, in a story offering thrills aplenty on a deserted island. A sure choice for a fast seller. Good item for school and public libraries.