Hardy Boys" Mystery Stories by F.W. Dixon - "All boys from 10 to 14 who like lively adventure stories, packed with mystery and action, will want to read every one of the "Hardy Boys" stories....
Sons of a famous American detective, the Hardy boys help solve many thrilling cases after school hours and during vacations, as they follow-up the clues they unearth in their quest to bring criminals to justice." (From the back cover)
Franklin W. Dixon
Grosset & Dunlap