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 50 Codes that Changed the World, Sinclair McKay explores these uncrackable codes, secret cyphers and hidden messages from across time to tell a new history of a secret world. From the temples of Ancient Greece to the court of Elizabeth I; from antique manuscripts whose codes might hold prophecies of doom to the modern realm of quantum mechanics, you will see how a few concealed words could help to win wars, spark revolutions and even change the faces of great nations. Here is the complete guide to the hidden world of codebreaking, with opportunities for you to see if you could have cracked some of the trickiest puzzles and lip-chewing codes ever created.