Two of the world's leading authorities on codebreaking reveal their techniques and tricks - interwoven with a treasure trove of authentic stories about famous code-cracking successes, and many still unsolved encryption mysteries. Elonka Dunin, codebreaker and an expert on the world's most famous unsolved codes, and Klaus Schmeh, one of the world's most prolific crypto-bloggers, describe the best-known traditional encryption techniques along with powerful methods to break them. In this book, you can learn about: · Beatrix Potter's encrypted diary, and how to read it. · The Zodiac Killer's four encrypted messages and how one of these was broken. · What to do with encrypted letters, postcards, and diaries in order to be able to analyse and decipher such documents - numerous examples are provided. · How to find free software tools that help you to break the majority of pencil-and-paper ciphers. · Many of the exceptions, i.e., encrypted documents that have so far withstood all attempts to solve them, including the Voynich Manuscript, the Kryptos inscription K4, and the three remaining messages of the Zodiac Killer. This is the perfect guide for anyone who is interested in breaking authentic codes and ciphers. It is ideal for historians and law-enforcement agents who might be confronted by encrypted messages, as well as for puzzle fans, geocachers, members of the American Cryptogram Association (ACA), and readers of Dan Brown's novels.