The Three Investigators are on the job once again, this time staying on a California ranch where The Moaning Cave has once again found its voice. The cave's legend says that it used to moan all the time after a El Diablo, famous 19th century Mexican outlaw, disappeared into the cave while being pursued by the law and was never found. Fifty years ago the cave abruptly stopped making noise. This renewed creepiness coincides with a series of minor accidents to ranch hands, who are convinced that it's the spirit of El Diablo causing both. Can Jupiter, Pete and Bob figure out the true cause before the ranch owner loses all his workers and is forced to sell the property?

This is the 10th book in this middle-grade mystery series, and the first written by William Arden. (Many juvenile mystery series were written by a series of authors, sometimes under a shared name and sometimes not.) The ebook version I have is apparently the British one, as the word "licence" is misspelled :) and Alfred Hitchcock, who introduces the boys' adventures in each book, is back to being a famous film director. Thanks to Liz and Steve, who are also reading along in this series, for spotting the differences in previous books.

The mystery here is ... fine? It felt a little flat to me, with the various plot lines being held together by the thinnest of threads. But it's still a fun read and is good inspiration for youngsters of the value of applying logic and observation to everyday problems. Hopefully those problems don't include haunted caves and staged accidents, though! ( )

Friends of Pete Crenshaw’s father, the Daltons, have recently purchased the Crooked Y Ranch. When a mountain cave on the property begins to moan mysteriously & strange accidents begin plaguing the ranch and its workers, Pete, Jupiter & Bob head out to investigate.

Almost everyone believes the secret of the moaning cave has something to do with the presence of El Diablo—a legendary desperado who disappeared into the mountain almost a century ago. The Three Investigators are positive that the eerie happenings are the result of nefarious human agency rather than the supernatural. There is no shortage of potential suspects as the boys begin their investigation: a gruff ranch foreman, a bookish professor of California History, a suspicious man sporting an eye patch & a facial scar, two incredibly crusty & eccentric old prospectors, & a ranch full of scared ranch hands. As the investigation progresses, our intrepid investigators uncover secret naval maneuvers, undercover agents, sneaky claim jumpers, & a cunning international jewel thief.

This is certainly not an example of one of the best entries in the Three Investigators series of mysteries, but it is an entertaining read nonetheless. ( )

Tenth in the "Alfred Hitchcock and the Three Investigators" series, complete with a cave that moans, a legendary bandito who won't stay dead, missing diamonds and a dark subterranean pool possibly inhabited by a mysterious creature called "The Old One". Not memorable, but a fun nostalgic read. ( )

This is the first of the series with a different author and you can tell. Just not as good as the previous books, not as exciting, plot not as well developed, characters just a little bit flat.
I enjoyed it but wouldn't recommend it unless you either have excess time or already own the book. ( )

I read this whole series of books around ages 9-12. For me, it was the Harry Potter of its day. The main characters are kids who are maybe 12 or 13, who find mysteries to explore with logic. This was a great series for budding scientists and the like. Highly recommended for kids. ( )