649 books • 49 series
The Clue of the Screeching Owl (Hardy Boys Mystery Stories, #9) (The Hardy Boys 2-in-1 mysteries, #5)
Hooded Hawk Mystery (Hardy Boys, #34) (Hardy Boys Mystery Stories, #29) (The Hardy boys mysteries, #8)
The Mystery of the Aztec Warrior (Hardy Boys, #43) (Hardy Boys (eBook), #43) (Hardy Boys Mystery Stories, #1) (Two-in-ones)