The Three Investigators was an American juvenile detective book series first published as "Alfred Hitchcock and the Three Investigators." It was created by Robert Arthur, Jr., who believed using a famous figure like movie director Hitchcock would attract attention. Random House, which is owned by Bertelsmann AG, is the U.S. publisher and still holds some of the rights to the books. Other rights are held by the heirs to Robert Arthur, Jr. and the German publisher, Kosmos. The Three Investigators are Jupiter Jones, Pete Crenshaw, and Bob Andrews.Most of the mysteries involved investigation of baffling phenomena (e.g., an ancient Egyptian mummy that whispered and a human skull that talked).

List of Books in the Download:
1. The Secret of Terror Castle
2. The Mystery of the Stuttering Parrot
3. The Mystery of the Whispering Mummy
4. The Mystery of the Green Ghost
5. The Mystery of theVanishing Treasure
6. The Secret of Skeleton Island
7. The Mystery of the Fiery Eye
8. The Mystery of the Silver Spider
9. The Mystery of the Screaming Clock
10. The Mystery of the Moaning Cave
11. The Mystery of the Talking Skull
12. The Mystery of the Laughing Shadow
13. The Secret of the Crooked Cat
14. The Mystery of the Coughing Dragon
15. The Mystery of the Flaming Footprints
16. The Mystery of the Nervous Lion
17. The Mystery of the Singing Serpent
18. The Mystery of the Shrinking House
19. The Secret of Phantom Lake
20. The Mystery of Monster Mountain
21. The Secret of the Haunted Mirror
22. The Mystery of the Dead Man's Riddle
23. The Mystery of the Invisible Dog
24. The Mystery of Death Trap Mine
25. The Mystery of the Dancing Devil
26. The Mystery of the Headless Horse
27. The Mystery of the Magic Circle
28. The Mystery of the Deadly Double
29. The Mystery of the Sinister Scarecrow
31. The Mystery of the Scar-Faced Beggar
32. The Mystery of the Blazing Cliffs
33. The Mystery of the Purple Pirate
34. The Mystery of the Wandering Cave Man
40. The Mystery of the Rogues' Reunion