Presents a guide to codemaking, codebreaking, and their role in history, describing different types of codes and ciphers, discussing codebreaking and concealment techniques, and including brief stories about exciting moments in the history of the art.

Jax and Ethan must decode an ancient Greek cipher to uncover the location of two magical urns before the urns are used to remove all faith and love from the world.

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 the difficult challenge yet -- a task no Cahill dared to imagine. When faced with a choice that could change the future of the world,...

While walking her poodle, Olivia Limoges discovers a dead body buried in the sand. Could the body be connected to the bizarre burglaries plaguing Oyster Bay, North Carolina? Can the Bayside Books Writers group decode the cliché clues left by the thieves?

As the race to find the 39 Clues builds to its explosive finish, Amy and Dan must explore an ancient culture and steal a clue guarded by thousands of the world's best-trained soldiers. It's the most dangerous search yet ... and it may mean the end for Amy and Dan.

It started with a kidnapping. A shadowy organization known only as the Vespers snatched seven members of the Cahill family and demanded a series of bizarre ransoms from around the world. Thirteen-year-old Dan Cahill and his older sister Amy began a global treasure hunt, determined to bring back whatever Vesper One needed, so long as it kept the hostages safe. But when they deliver the last ransom, Amy and Dan discover Vesper One's terrifying endgame....

Told in multiple voices, fifteen-year-old Jamaican Louisa Adair uncovers an Enigma machine in the small Scottish village where she cares for an elderly German woman, and helps solve a puzzle that could turn the tide of World War II. 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...

657 days ago Meg's British father left their home in France to fight the Nazis, leaving some codes in a jar for her to decipher, and Meg and her French mother moved to the Perche, a region in France near Normandy known for its forests; now Meg watches the German soldiers in town, and sometimes carries messages for the French resistance--but suddenly things have gotten much more dangerous: there is a wounded British officer hiding in her grandmother's...