From the ingenious ciphers of Italian princes to the spy books of the Civil War to the advanced techniques of the CIA, codes and code breaking have played important roles throughout history.

Describes various codes and ciphers that have been difficult and some impossible to crack.

When a new book arrives at the library with a secret code written inside, Derek, with the help of his friends, follows the clues from one novel to the next and makes a discovery that may help him get past a terrible loss.

"SHINE's solar energy station is under threat from evil agency SHADOW. Special Agent EJ12 needs to lighten up. She must crack SHADOW's codes and overcome her fears to stop them before they turn the lights out on the SHINE network. That's the easy part. As EJ12, Emma Jacks can do anything. So why is she worried about going to her best friend's slumber party?"--

Shaken by a shocking loss, Amy and Dan flee to an exotic land and trace the footsteps of their most formidable ancestor yet: a military leader of mythic proportions.

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,...

The shadow of the man in black has followed fourteen-year-old Amy Cahill and her younger brother Dan on their worldwide search for 39 Clues that lead to a great power. The man has tried to kill them and he is a Madrigal, as were their parents. And now the man is ready to step out of the darkness for their final confrontation.

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....

Chronicles the first Vesper attack on Jan van Eyck's altarpiece at Ghent in the 1600s, then jumps to WWII and young Grace Cahill's desperate bid to save the masterwork from the Nazis.

"Elusive art thief Lars Heinrich returns to New York City looking to settle a score. Super sleuth seventh-grader Edmund Xavier Lonrrot will need not only his photographic mind and artistic talents, but any skill he possesses with cracking codes as a string of the city's historical monuments become potential clues in what could become one of the greatest heists in history"--