Frank and Joe join their friend Jack and his father in hunting a lost treasure.

The Secret of the Old Mill is an enthralling mystery novel from the beloved Hardy Boys series, penned by Franklin W. Dixon. In this captivating tale, brothers Frank and Joe Hardy, amateur sleuths with a knack for solving crimes, find themselves embroiled in a perplexing case that leads them deep into the heart of an old mill shrouded in secrecy. The adventure begins when the Hardy boys stumble upon a cryptic message hidden in a hollow tree, hinting...

Teenage detective Nancy Drew uses her courage and powers of deduction to solve the mysterious happenings in an old stone mansion.

Nate the Great solves the mystery of the missing picture.

While trying to locate a missing dancer who is about to gain a large inheritance, Nancy Drew finds a clue leading to the solution of yet another mystery.

Ten brief cases allow the reader to match wits with ten-year-old crime-buster, Encyclopedia Brown, as he locates stolen jewels, solves a bank robbery, and more. Solutions are included at the back of the book.

Nancy Drew determines if an ivory elephant charm really protects its wearer from harm when she investigates the involvement of a member of the Bengleton Wild-Animal Show in a mysterious scheme.

The Hardy boys track down the saboteurs who kidnapped their father.

Nate the Great investigates the mysterious disappearance of the purple plastic octopus that his baseball team uses for second base.

When Frank and Joe Hardy investigate a hijacking, they become involved with industrial spies and a pursuit into the Canadian wilderness.