Nearly two years ago, Meg Kenyon's father left their home in France to fight for the allies in World War II. Recently, Meg heard he had been taken prisoner by the Nazis. All Meg has left of him now are the codes he placed in a jar for her to decipher, an affectionate game the two of them once shared. But even those are running low. But the codes are running low, and soon there'll be nothing left of Papa for Meg to hold on to at all. Suddenly, an impossible...

"To crack a secret code, Mac follows the clues to France and Japan where he must use his gaming skills and defeat his enemy, the KGB Man."--

When the NSA's invincible code-breaking machine encounters a mysterious code it cannot break, the agency calls its head cryptographer, Susan Fletcher, a brilliant and beautiful mathematician. What she uncovers sends shock waves through the corridors of power. The NSA is being held hostage...not by guns or bombs, but by a code so ingeniously complex that if released it woud cripple U.S. intelligence. Caught in an accelerating tempest of secrecy...

Throughout the hunt for the 39 Clues, Amy and Dan Cahill have uncovered history's greatest mysteries and their family's deadliest secrets. But are they ready to face the truth about the Cahills and the key to their unmatched power? After a whirlwind race that's taken them across five continents, Amy and Dan face the most difficult challenge yet -- a task no Cahill dared to imagine. When faced with a choice that could change the future of the world,...

When a strange coded message arrives at 221B Baker Street, sent by a member of Professor Moriarty's criminal organization, Sherlock Holmes soon deciphers it and finds a warning: someone is about to be murdered. A visit from a Scotland Yard inspector confirms that one John Douglas has been mysteriously killed in Sussex. Even Sherlock Holmes, well accustomed to the bizarre, finds the elements of this case unusual. John Douglas lived at Birlstone

...

A German soldier risks his life to drop off the sought-after Enigma Machine to British Intelligence, hiding it in a pub in a small town in northeast Scotland. Louisa Adair, a teen girl hired to look after the pub owner's elderly, German-born aunt, Jane Warner, finds it but doesn't report it. Flight-Lieutenant Jamie Beaufort-Stuart intercepts a signal but can't figure it out. Ellen McEwen, volunteer at the local airfield, acts as the go-between and...

When Quentin Herms is chased from his village into the Quag, a dark forest filled with terrifying beasts and murderous Outliers, Vega uses her skills as a talented decoder to uncover dangerous secrets.

When Cody's younger sister disappears in Magicland, it is up to the Code Busters to solve puzzles and messages to find her. Back matter includes keys to the codes and solutions to the coded messages that appear throughout the text.

Charlie, Anna, and Emily must overcome their differences and work together to solve various puzzles leading to the secret treasure a famous female explorer left in Idlewood Manor before the adults do.

Describes how African Americans made coded quilts and how they used them to escape on the underground railroad.