Frank and Joe Hardy are the sons of Fenton Hardy, a famous private detective. Finding everyday life at home in Bayport dull, the boys hope their father will let them work on one of his cases. Disappointed when he tells them his work is too dangerous for children, they are more determined than ever to follow in their dad's footsteps, and solve mysteries.

The sons of the great detective Fenton Hardy, Frank and Joe are eager to impress their father with their mystery solving skills.

Marty Markham, a rich orphan, attends summer camp at a dude ranch where he gradually learns to love outdoor life and becomes best friends with the popular Spin Evans.

Three men track down a pack of Dobermans and along with a young Native American boy, train the Dobermans to rob the campaign funds of a politician.

A Major noted for advancing with his mouth before thinking is given a choice: to be drummed out of the Army, or take command of and shape up the ROTC program at Sheridan Academy before it fails its next inspection. At Sheridan he encounters three hundred pre-teen cadets who range from rascally to adorable, and a female doctor who has just the right prescription for him.

The story of Franklin Roosevelt's bout with polio at age 40 in 1921 and how his family (and especially his wife Eleanor) cope with his illness. From being stricken while vacationing at Campobello to his triumphant nominating speech for Al Smith's presidency in 1924, the story follows the various influences on his life and his determination to recover.