"A fascinating exploration of the uncrackable codes and secret cyphers that helped win wars, spark revolutions and change the faces of nations. There have been secret codes since before the Old Testament, and there were secret codes in the Old Testament, too. Almost as soon as writing was invented, so too were the devious means to hide messages and keep them under the wraps of secrecy. In The Hidden History of Code Breaking, Sinclair McKay explores...

Provides an overview of the ciphers, codes, algorithms, and keys used in real-life situations to keep people's information safe and secure.

A four-thousand-year history of cryptography ranges from the time of the ancient Egyptian pharaohs to the present, explaining encryption's development and evolution, looking at famous codes, and offering clues for code-breaking.

Twins Josh and Danny continue following clues leading them to marbles filled with scientific code, despite the fact that mad scientist Petty Potts' REPTOSWITCH formula is having some very strange side-effects.

Betrayed by their cousins, abandoned by their uncle, and with only the slimmest hint to guide them, Amy and Dan rush off to Egypt on the hunt for 39 clues that lead to a source of unimaginable power.

"The members of the Code Busters Club take a class trip to Angel Island--the Ellis Island of the West--where they discover a mysterious box with a connection to one of the Code Busters"--

Twins Danny and Josh reveal to neighbor Petty Potts that they have been on a quest to find marbles containing secret code and soon find themselves--as geckos--in her new secret laboratory within the very pink Princessland.

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.

While on vacation with their parents in Cornwall, twins Danny and Josh follow clues to another marble but find themselves trapped by the tide on a rocky island and the only way back is to use some pilfered REPTOSWITCH.

Four women who worked as codebreakers at Bletchley Park have taken up civilian lives. Susan has collated data about a series of murders. She tries to persuade the police she knows where another body is, but they are unable to locate it and dismiss her. She turns to her three friends and they work out where the next victim will be taken, find the body, and then decide they are the only ones who can track down the killer.