About the book: Spies of the First World War is the first popular account of the history of international espionage in the first decades of the twentieth century. This collection of essays on intelligence activities around the world before and during the First World War begins with an account of the spy fever in early 20th-century Britain that led to the creation of MI5 and MI6. It tells about the White Lady spy network in German-occupied Belgium, about the successes of English codebreakers who deciphered the famous “Zimmerman telegram”, about the execution of Mata Hari and Edith Cavell and about many other well-known and long-forgotten intelligence officers, agents, intelligence organizers, detectives, as well as about traitors and defectors. The book was the result of research that the author was engaged in in several countries around the world, but most of the information was taken from materials stored in the National Archives of the United Kingdom, under whose patronage this book was published in 2010 .