While the Clock Ticked:
A banker who has been receiving threatening notes enlists the help of the Hardy boys. Before long, the young sleuths find themselves entangled in the investigation of a notorious band of thieves.

Footprints Under the Window:
Frank and Joe attempt to foil a ruthless espionage ring in their effort to sabotage the United States space program.

The Mark on the Door:
In their motorboat the Sleuth Frank and Joe Hardy search Barmet Bay for a dangerous stranger who has stolen a valuable boat.

The Hidden Harbor Mystery:
The boys once again have jumped into the thick of a complicated mystery.

The Sinister Signpost:
In one of the most dangerous and intriguing cases of their careers, Frank and Joe Hardy help their father investigate a series of mysterious car accidents.

A Figure in Hiding:
A blind peddler’s warning and a weird glass eye plunge Frank and Joe Hardy into one of the most baffling cases they have ever tackled.

The Secret Warning:
Strange events involve Frank and Joe Hardy in a mystery which shrouds an ancient treasure–the golden head of the Pharaoh Rhamaton IV.

The Twisted Claw:
A series of museum thefts launch the Hardy Boys on this baffling mystery.

The Disappearing Floor:
Once again Frank and Joe Hardy take on a puzzling case when their famous detective father asks the boys to assist him in tracking down a notorious jewel thief and his accomplices.

Mystery of the Flying Express:
A sleek new hydrofoil is scheduled to start ferrying passengers between Bayport and Cape Cutlass.