After a dying criminal confesses that his loot has been stashed "in the tower", the Hardy boys make an astonishing discovery.,

Join the Hardy Boys in their search for a missing young professor that leads them to the Honeycomb Caves where they are met by dangerous encounters.

Someone stole 'Old Rusty,' Ralphie Jordan's trusty bicycle. Jigsaw and Mila hit the trail to track down the thief. But one piece of the puzzle doesn't fit. Who would take a hand-me-down bike? Solving this case is an uphill ride for ace detectives Jigsaw and Mila.

The Hardy boys embark on another puzzling mystery when they try to discover who is stealing rare collections of ancient pirate treasure and smuggling them out of the United States.

Encyclopedia Brown, boy detective extraordinaire, solves ten new cases, including "The Case of the Miracle Pill," "The Case of Nemo's Tuba," "The Case of the Lawn Mower Races," and "The Case of the Air Guitar." Solutions provided at the end of each chapter.

"Drop case or else danger for you and your family." This warning addressed to Fenton Hardy not only alarm the famous investigator and his detective sons, but also puzzles them, because Mr. Hardy is working on more than one case. Which one prompted the threat? When more ominous warnings follow, Frank and Joe suspect there is a link between the counterfeiting case they are investigating and a secret case their father cannot discuss since it involves...

The Alden children hunt for their late grandmother's necklace that has been missing for years.

Ten brief cases allow the reader to match wits with ten-year-old crime-buster, Encyclopedia Brown, as he locates stolen jewels, retrieves a stuffed tiger, and more. Solutions are included at the back of the book.

A wounded homing pigeon carrying a mysterious message lands in Nancy's yard and she finds herself investigating the workings of a sanatorium.

Joe, Frank, and their friends search the icebound Cabin Island for a missing boy and some stolen medals.