39 books in series
Hardy-guttene
Hardy-guttene is a 39-book series with 39 primary works first released in 1920 with contributions by Franklin W. Dixon, Jerrold Mundis, and Leslie H. Morrill.
 The Tower Treasure
| 3.5 | 34 reads | |||
 The House on the Cliff
| 3.5 | 16 reads | |||
 The Secret of the Old Mill The Secret of the Old Mill
| 3 | 2 reads | |||
 The Missing Chums
| 3 | 7 reads | |||
 Hunting for hidden gold
| 3.67 | 8 reads | |||
 While the Clock Ticked
| 3.6 | 7 reads | |||
 The Hidden Harbor Mystery
| 3 | 4 reads | |||
 The Secret Warning
| 3 | 4 reads | |||
 The clue of the broken blade
| 3 | 3 reads | |||
 The flickering torch mystery
| 3.33 | 4 reads | |||
 The Secret Panel
| 3.3 | 6 reads | |||
 The sign of the crooked arrow
| 3 | 3 reads | |||
 The Wailing Siren Mystery
| 3 | 3 reads | |||
 The Yellow Feather Mystery
| 3 | 4 reads | |||
 The Secret of Pirates' Hill
| 3.33 | 4 reads | |||
 The Clue in the Embers
| 3 | 3 reads | |||
 The Ghost at Skeleton Rock
| 3.33 | 4 reads | |||
 Mystery at Devil's Paw
| 3 | 3 reads | |||
 The mystery of the Chinese junk
| 3 | 3 reads | |||
 Mystery of the Desert Giant
| 3.5 | 5 reads | |||
 The Viking Symbol Mystery
| 3 | 3 reads | |||
 The mystery of the spiral bridge
| 3 | 3 reads | |||
 Footprints under the window
| 3 | 3 reads | |||
 Mystery of the Whale Tattoo
| 3 | 3 reads | |||
 The great airport mystery
| 3 | 5 reads | |||
 The Bombay Boomerang
| 3 | 3 reads | |||
 Masked Monkey
| 3 | 4 reads | |||
 The Shattered Helmet
| 3.5 | 5 reads | |||
 The Mysterious Caravan
| 3.33 | 5 reads | |||
 The Witchmaster's Key
| 3 | 3 reads | |||
 The Firebird Rocket
| 3 | 5 reads | |||
 Mystery of Smugglers Cove
| 3 | 3 reads | |||
 The Vanishing Thieves
| 3 | 2 reads | |||
 Track of the Zombie
| 3 | 1 read | |||
 The Voodoo Plot
| 4 | 2 reads | |||
 Tic-Tac-Terror
| 3 | 1 read | |||
 Trapped at Sea
| 3 | 1 read | |||
 Game Plan for Disaster
| 3 | 1 read | |||
 The Crimson Flame
| 3.5 | 2 reads |