Mystery - The Hardy Boys Nystery #4.

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.

Teenage detectives Frank and Joe Hardy investigate a case of counterfeiting.

The Hardy Boys series, first published in 1927, has sold more than 70 million copies! Now with a brand-new look, this is an edition that collectors won't want t

The Hardy Boys series, first published in 1927, has sold more than 70 million copies! Now with a brand-new look, this is an edition that collectors won't want t