Hardcover
(Random House Books for Young Readers, Sept. 12, 1968)
HC, 1968, ex library, cover shows wear and rubbing along edges, corners, and spine, tape reinforces the hinges inside both front and back cover, smudges on fore edge, clean inside, tight binding.
The twelfth book in the ORIGINAL Three Investigators series. An unusual title, an unusual mystery, and an unusual solution by Jupiter Jones, Bob, and Pete. An insane laugh from a hunchback???? Another classic with the usual intro from Alfred Hitchcock!!!!
Paperback
(Random House Books for Young Readers, Sept. 12, 1986)
While attending a week-long family reunion on a California island, the Three Investigators find their photographs of the event hold an inordinate interest for someone else, and receive clues to that unknown identity from both an ancient and a modern boating accident.
Paperback
(Random House Books for Young Readers, May 21, 1991)
Many years ago, the young bandit El Diablo disappeared into a cave, never to be seen again. Now an eerie moaning sound is coming from his old hideout, and the ranchers who live nearby think he may still be alive.The Three Investigators set out to explore the moaning cave--and soon wish they had come armed with more than a flashlight!