Pearson's groundbreaking study of the art and science of secret writing remains a classic of the genre. Drawing on a wide range of historical and literary sources, he provides a compelling overview of the many different methods of code and cipher creation and decoding, from ancient times to the present day. With its engaging prose and fascinating insights, this book is a must-read for anyone interested in cryptography or espionage. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.