Explains in simple terms how to encode and decode messages in various ciphers, describes coding machines, and gives formulas for invisible ink.

Examines the ways in which mathematics has been used in warfare, from navigation, mapping, and ballistics to the use and breaking of codes and cyphers, especially the World War II Engima system, logistics, and record-keeping.

John Plummer refused to abandon hope for his children, even in death. He left behind…A briefcase full of SecretsAn evil his two children may not escapeSeven Ciphered riddles that must be solvedAn inheritance that may not be attainedA book that holds the KeyIn the darkest hour of their lives, Cadence and Timbre Plummer find an unlikely path forward in the expectation of an inheritance their father may have placed out of their reach. Their troubled...

Award of Merit winner, Novella category, 2013 HOLT Medallion contestAbigail can't explain, even to herself, why she married Derek after he'd asked her to wait for him and then became engaged to someone else. If his poor fiancée had not died, he would now be wed to her instead of Abigail. But then Abigail begins uncovering some of the secrets that are a part of her husband's life and wonders if perhaps there is hope for their marriage after all.Derek,...

An examination of one of the most important yet underexplored aspects of World War II--intelligence--shows how espionage successes and failures by the United States, Britain, Russia, Germany, and Japan influenced the course of the war and its final outcome.

200 years ago, Thomas J. Beale hid a treasure and wrote a cipher that has been unbreakable until today...that is until Calla Cress starts to read it. Now, some secrets are too dangerous to know. Nursing a past loss and failure, artifacts handler, codebreaker, and government agent, Calla Cress is framed for the disappearance and murder of the ISTF spy agency's Chief of technology and science, her best friend, Jack Kleve. All is not as it seems. When...

Ancient mariners search the seven seas to discover the ancient world of vast treasures that have eluded famous pirates across the centuries. Ophir is an insight into the world of so called secret codes used to veil a true secret and a young George Anson , Captain William Kidd and other infamous sea rovers share a secret that many men have died for. Captain William Kidd was murdered by the British state and the codes of Shugborough hall are being constructed...

¡Sumérgete en la historia secreta de... los secretos! Las persona han querido ocultar mensajes e información importante durante milenios. Lee cómo los códigos y cifrados más geniales de la historia progresaron desde cinturones y palos hasta discos giratorios y supercomputadoras. Usa tus habilidades criptológicas para diseñar tu propio cifrado secreto. También aprende sobre las personas inteligentes que construyeron y rompieron los sistemas...