mystery and detective stories

On a visit to Germany the Hardy brothers investigate the theft of plans for a newly invented submarine and the mysterious disappearance of valuable coins and paintings.

Their search for an Easter Island idol takes the Hardy boys to Easter Island and on to investigate the theft of government material in Antarctica.

Frank and Joe go to Florida to investigate the sabotage of a satellite launch and uncover a theft ring involving sea animals.

Valuable antique weathervanes are being stolen in the Pennsylvania Dutch country. A Navy employee removes a top secret document from the Pentagon. The Hardy brothers try to solve these two seemingly unrelated mysteries.

The Hardy Boys are given clues which send them in search of the treasure hidden by the Outlaw of the Pine Barrens.

When a ferocious, wolf-life creature appears in a small town, the Hardy boys are engaged to clear the name of a young man who has a history of werewolves in his family.

A Japanese business tycoon mysteriously disappears and, soon after, a rare samurai sword is stolen from an art gallery. Suspecting a connection, the Hardy boys try to solve the mystery.

The Hardy boys track a criminal who plans to use an invention designed as a peaceful aid to harm the free world instead.

The Hardy brothers travel to an Arizona ranch and eventually, Thailand in pursuit of jewel thieves who have stolen a priceless ruby.

A "monster" who terrorizes Bayport and a girl who runs away to join a cult are the subjects of the Hardy boys' sleuthing.