GROSSET & DUNLAP, Publishers, NEW YORK

THE HARDY BOY’S SERIES

By FRANKLIN W. DIXON

Illustrated. Every Volume Complete in Itself.

THE HARDY BOYS are sons of a celebrated American detective, and during vacations and their off time from school they help their father by hunting down clues themselves.

THE TOWER TREASURE

A dying criminal confessed that his loot had been secreted “in the tower.” It remained for the Hardy Boys to make an astonishing discovery that cleared up the mystery.

THE HOUSE ON THE CLIFF

The house had been vacant and was supposed to be haunted. Mr. Hardy started to investigate—and disappeared! An odd tale, with plenty of excitement.

THE SECRET OF THE OLD MILL