What is the third Hardy Boys book?
The Secret of the Old Mill
The Mystery of the Phantom Ranch
The Hidden Staircase
The Mystery of the Phantom Ranch
The Hidden Staircase
The Mystery of the Blue Train
The Secret of the Unicorn
The Hidden Staircase
Mystery at Loch Ness
The Mystery of the Blue Train
The Hardy Boys Mystery
The Mystery of the Phantom Ranch
The Hardy Boys Mystery Stories
The Black Hole of Calcutta
Mystery of the Phantom Ranch
The Hardy Boys in the Lost Valley
The Hidden Staircase
The Hardy Boys in the Caribbean
The Hardy Boys in the Jungle
The Secret of the Unicorn
Mystery at Loch Ness
The Hardy Boys Mystery
The Hardy Boys in the South Seas
The Hardy Boys in the Avocado Jungle
The Hardy Boys Mystery Hour
The Hardy Boys Mystery Stories
The Mystery of the Black Cat
The Mystery of the Phantom Flame
The Hardy Boys in the Wild West
The Secret of the Unicorn Cave
The Mystery of the Phantom Ranch
The Hardy Boys in the Lost Valley
The Hidden Staircase
The Mystery of the Blue Train
The Hardy Boys in the Caribbean
Mystery of the Phantom Ranch
The Hardy Boys in the Jungle
The Lost Treasure of the Sierra Madre
Mystery at Loch Ness
The Hardy Boys in the Lost World
The Black Hole of Calcutta
The Hardy Boys Mystery
The Hardy Boys Mystery of the Lost Treasure
The Hardy Boys in the Avocado Jungle
The Hardy Boys Mystery Hour
The Hardy Boys Mystery of the Lost Island
The Hardy Boys Mystery Stories
The Hardy Boys Mystery of the Phantom Ranch
The Secret of the Unicorn
The Hardy Boys in the Wild West
The Lost Treasure of Montezuma Creek
Dead Man's Curve
The Hidden Staircase
The Hardy Boys in the Lost Valley
The Secret of the Unicorn Cave
The Hardy Boys Casebook
The Hardy Boys in the Caribbean
The Hardy Boys in the Jungle
Dead Man's Chest
Mystery at Loch Ness
The Mystery of the Blue Train
Mystery of the Phantom Ranch
The Hardy Boys Mystery
The Hardy Boys in the Lost World
The Phantom of the Opera
The Mystery of the Phantom Ranch
The Hardy Boys Mystery of the Lost Treasure
The Hardy Boys in the Avocado Jungle
The Hardy Boys Mystery Hour
The Hardy Boys Mystery Stories
The Hardy Boys Mystery of the Lost Island
The Secret of the Unicorn Mountain
The Hardy Boys Mystery of the Phantom Ranch
The Lost Treasure of Montezuma Canyon
The Hardy Boys in the Wild West
The Hidden Staircase
The Hardy Boys in the South Seas
The Hardy Boys in the Lost Valley
The Hardy Boys Adventures in the Caribbean
Dead Man's Curve
The Hardy Boys Casebook
The Black Hole of Calcutta
The Hardy Boys in the Caribbean
Jungle Drums of Darkest Africa
The Hardy Boys in the Jungle
Mystery at Loch Ness
The Hardy Boys Mystery
The Treasure of Montezuma Canyon
The Hardy Boys in the Lost World
The Lost Treasure of the Sierra Madre
The Secret of the Unicorn Cave
Dead Man's Chest
The Hardy Boys Mystery Hour
The Lost Treasure of Montezuma Creek
The Hardy Boys in the Avocado Jungle
The Hardy Boys Mystery Stories
The Lost Treasure of San Lorenzo
The Mystery of the Phantom Ranch
The Hardy Boys Mystery of the Lost Treasure
The Hardy Boys Mystery Magazine
The Hardy Boys Mystery of the Lost Island
The Hardy Boys in the Wild West
The Hidden Staircase
The Hardy Boys Mystery of the Phantom Ranch
The Hardy Boys in the Lost Valley
The Lost Treasure of the Sierra Madre.
The Lost Treasure of the Incas
The Hardy Boys Casebook
Dead Man's Ransom
The Hardy Boys Adventures in the Amazon
The Hardy Boys in the Caribbean
The Hardy Boys in the Jungle
The Lost Treasure of Atlantis
The Hardy Boys Mystery
The Lost Treasure of Montezuma Flats
The Lost Treasure of Montezuma Castle
Dead Man's Curve
The Hardy Boys in the Lost World
The Hardy Boys Adventures in the Caribbean
The Lost Treasure of the Sierra Madres
Hidden Treasures of the Sierra Madre
The Lost Treasure of Montezuma Canyon
The Hardy Boys Mystery Stories
Mystery of the Phantom Ranch
The Lost Treasure of Montezuma
Tombstone Trap
The Black Hole of Calcutta
The Hardy Boys Mystery of the Lost Treasure
The Hidden Staircase
The Treasure of Montezuma Creek
Dead Man's Chest
The Phantom of the Opera
The Hardy Boys Mystery of the Lost Island
The Hardy Boys Adventures in Alaska
Jungle Drums of Darkest Africa
Murder in the Rue Morgue
The Hardy Boys in the Lost Valley
The Hardy Boys Casebook
The Hardy Boys in the Caribbean
The Hardy Boys Mystery
The Mystery of the Phantom Ranch
The Hardy Boys in the Jungle
The Hardy Boys in the Avocado Jungle
The Black Hole of Calico
The Hardy Boys Mystery Hour
Hidden Treasures of the Hardy Boys
The Hardy Boys Adventures in Mexico
Dead Man's Walk
Dead Man's Ransom
The Hardy Boys in the Lost World
The Hardy Boys Mystery Magazine
The Hardy Boys Adventures in the Amazon
Return to Treasure Island
The Hardy Boys Mystery Stories
Dead Man's Curve
The Hardy Boys in the Wild West
Tombstone Trap
Scooter's Last Case
The Lost Treasure of Monterey
The Hardy Boys Adventures in the Caribbean
The Lost Treasure of the Sierra Madre!
The Hidden Staircase
Scooter's Last Stand
Mystery of the Phantom Ranch
Scooter's Great Escape!
Treasure Island
Scooter's Curse
The Lost Treasure of Montezuma Creek
Jungle Drums of Darkness
Jungle Drums of Death
The Lost Treasure of Atlantis
Dead Man's Chest
The Hardy Boys in the Lost Valley
The Hardy Boys Casebook
The Lost Treasure of the Sierra Madre.
The Hardy Boys in the Caribbean
The Lost Treasure of Montezuma Castle
The Hardy Boys Mystery
The Hardy Boys Adventures in Alaska
The Treasure of Montezuma's Treasure
The Treasure of Montezuma's Gold
The Hardy Boys Mystery Hour
Mystery at Loch Ness
The Mystery of the Phantom Ranch
The Treasure of Montezuma Hill
Hardy Boys Adventures in the Lost World
Dangerous Curves
The Hardy Boys in the Lost World
Tombstone Vendetta
The Lost Treasure of Montezuma
The Hardy Boys Mystery Stories
Tombstone Trap
Hidden Treasures of the Sierra Madre
The Lost Treasure of the Incas
Hardy Boys Adventures in the Jungle
Treasure Island
The Hidden Staircase
Dead Man's Curve
The Hardy Boys Adventures in the Caribbean
Dead Man's Ransom
Dead Man's Walk