While searching in Iceland for a missing sailor sought by an insurance company, the teen-age detective brothers uncover a plot threatening the life of a United States astronaut and the secrets of NASA's moon project.

Frank and Joe, the Hardy boys, solve a mystery involving a magician, American secret agents, and international spy ring, and a Scottish castle.

When the Hardy Boys set out to solve the mystery of their missing chums, they discover a gang hide-out in a cave on an island along the way.

Frank and Joe solve a mystery involving the disappearance of a professor, a hot-tempered hermit, sabotage at the station, and the Honeycomb Caves.

When valuable electronic parts are stolen from shipments made by Stanwide Mining Equipment Company's cargo planes, the boys go undercover as employees to track down the thief.

"Frank and Joe are excited for the school's annual talent show! Frank is working backstage, and Joe is going to show off his sweet juggling skills. Someone keeps playing pranks on all the acts-- bubbles are found in someone's trumpet and someone's music is replaced with the sound of croaking frogs!"--Jacket.

"Frank and Joe try to hit a home run by figuring out what happened to the Bayport Bandits' playbook before the first big baseball game in the second book in an all-new, interactive Hardy Boys chapter book mystery series. Includes space for readers to jot down their own ideas and solutions to the case! Frank and Joe and the rest of their Bayport Bandits teammates can't wait for Little League to start! Everyone is celebrating the beginning of the season...

When the Hardy boys eagerly agree to assist their friend Jack Dodd and his father in locating a family treasure, the two young detectives are unaware of the baffling complications that will arise. The only clue to the long-lost treasure is a cryptic message written by a Pilgrim ancestor. But when Mr. Dodd and Jack are accused of stealing cars and then mysteriously disappear, Frank and Joe are confronted with a triple mystery. Have their friends run...

When their detective father asks them to play burglar in order to protect a client's valuable invention from thieves, the Hardy boys find themselves involved in a large and dangerous conspiracy.