117 books in series

The Hardy Boys

The Hardy Boys is a 117-book series with 117 released primary works first released in 1920 with contributions by Franklin W. Dixon, Jerrold Mundis, and Leslie H. Morrill.

The Tower Treasure
The House on the Cliff
Cover 7

The Secret of the Old Mill

The Missing Chums
Hunting for hidden gold
The Shore Road Mystery
The Secret of the Caves
Mystery of Cabin Island
The great airport mystery
What Happened at Midnight
While the Clock Ticked
Footprints under the window
The Mark on the Door
The Hidden Harbor Mystery
The Sinister Sign Post
A Figure in Hiding (Hardy Boys, #16)
The Secret Warning
The Twisted Claw
The mystery of the disappearing floor.
Mystery of the Flying Express
The clue of the broken blade
The flickering torch mystery
The Short-Wave Mystery
The Secret Panel
The Phantom Freighter
The Secret of Skull Mountain
The sign of the crooked arrow
The Wailing Siren Mystery
The Secret of Wildcat Swamp
The Crisscross Shadow
The Yellow Feather Mystery
The Clue in the Embers
The Secret of Pirates' Hill
The Ghost at Skeleton Rock
Mystery at Devil's Paw
The mystery of the Chinese junk
Mystery of the Desert Giant
The Viking Symbol Mystery
The Mystery of the Aztec Warrior
The mystery of the spiral bridge
The hooded hawk mystery
Mystery of the Whale Tattoo
The Arctic patrol mystery.
The Bombay Boomerang
Danger on Vampire Trail
Masked Monkey
The Shattered Helmet
The Clue of the Hissing Serpent
The Mysterious Caravan
The Witchmaster's Key
The Jungle Pyramid
The Firebird Rocket
The Sting of the Scorpion
Mystery of the Samurai Sword
El espia del Pentagono
The Apeman's Secret
The Mummy Case
Mystery of Smugglers Cove
The Stone Idol
The Vanishing Thieves
The Outlaw's Silver
The submarine caper
Cover 3

The Four-Headed Dragon

The Infinity Clue
Track of the Zombie
The Voodoo Plot
The Billion Dollar Ransom
Tic-Tac-Terror
Trapped at Sea
Game Plan for Disaster
The Crimson Flame
Cave-In
Sky Sabotage
The roaring river mystery
Demon's Den
The Blackwing Puzzle
The Swamp Monster
Revenge Of The Desert Phantom
The Skyfire puzzle
The Mystery of the Silver Star
The Hardy Boys Program for Destruction
Tricky Business
Sky Blue Frame
Danger on the Diamond
Shield of Fear
The Shadow Killers
The Serpent's Tooth Mystery
Breakdown in Axeblade
Wipeout
Cast of Criminals
Terminal Shock
Three-Ring Terror
High Speed Showdown
The Alaskan Adventure
Lost in Gator Swamp
The Secret of Skeleton Reef
Cover 3

The Crisscross Crime

Cover 2

Danger in the Extreme

The Caribbean Cruise Caper
Cover 2

The Lure of the Italian Treasure

Training for Trouble
The End of the Trail
Skin & Bones
Crime in the Cards
Past and Present Danger
Trouble in Warp Space
Trick-or-Trouble
In Plane Sight
The Case of the Psychic's Vision
The Mystery of the Black Rhino
Cover 8

Passport to Danger

Typhoon Island
The Secret of the Soldier's Gold
Cover 5

The Dangerous Transmission

One False Step
Motocross Madness
Cover 1

Hardy Boys, 4 Volumes Boxed Set