The legend of the golden key
Tom McCaughren
Four young boys find adventure involving ghosts and buried treasure when they set out to discover the secret behind the old legend of the golden key.

by David D. Connell and Jim Thurman (1994)
Mathnet detectives Kate Monday and George Frankly use math skills like triangulation and scale to find a buried treasure in a ghost town.
Tom McCaughren
Four young boys find adventure involving ghosts and buried treasure when they set out to discover the secret behind the old legend of the golden key.
Donald J. Sobol
Leroy Brown is back in the next six books in the Encyclopedia Brown series. As Idavilles ten-year-old star detective, Encyclopedia has an uncanny knack for trivia. With his unconventional knowledge, he solves mysteries for the neighborhood kids through his own detective agency. But his dad also happens to be the chief of the Idaville police department, and every night around the dinner table, Encyclopedia helps him solve some of the most baffling crimes. With ten confounding mysteries in each book, not only does Encyclopedia have a chance to solve them, but readers are given all the clues as well and can chime in with their own solutions. Interactive and funits classic Encyclopedia Brown!
Bob Schaller
While Ashley and Adam Arlington are on vacation with their parents in Florida, they help solve an old mystery that involves the Seminole chief Osceola, the Spanish explorer Ponce de León, and the Castillo de San Marcos, a fort in Saint Augustine.
book created by A.E. Parker
Who helped the cat burglar open the safe? -Was it Miss Scarlet in the Lounge with the Candlestick? -Was it Colonel Mustard in the Dining Room with the Revolver? -Was it Mrs. Peacock in the Ball Room with the Knife? Mr. Boddy has invited his six best friends to be guests at his mansion for the weekend. When this weird and wacky crew get together, anything can happen. Follow along with their antics as you match up characters and crimes. Exciting mind-bending mini-mysteries to test your ability as a sleuth!