THE SECRET OF THE CAVES
When the boys reached the caves they came unexpectedly upon a queer old hermit.
THE MYSTERY OF CABIN ISLAND
A story of queer adventures on a rockbound island.
THE GREAT AIRPORT MYSTERY
The Hardy Boys solve the mystery of the disappearance of some valuable mail.
THE TED SCOTT FLYING STORIES
By FRANKLIN W. DIXON
Illustrated. Each Volume Complete in Itself.