**Joel Greenberg** is an author and historian who researches and writes about signals intelligence and its impact on two world wars. He is the author of Gordon Welchman, Bletchley Park's Architect of Ultra Intelligence. His book is the basis of a joint BBC/Smithsonian Network 2015 documentary about Welchman: The Forgotten Genius of Bletchley Park. He is also the author of Alastair Denniston, Code-breaking from Room 40 to Berkeley Street and the Birth of GCHQ. The book is both a biography of Denniston and an account of signals intelligence from its early development to the birth of GCHQ. Denniston was the first Head of GCHQ and the book was launched at its headquarters on 7 September 2017 in his honour.
"""...will be of great interest to those who wonder about wartime life at Britain's best known SIGINT organization.""-- ""Studies in Intelligence"" ""The book is well organized, nicely printed, and each of Main Contributors gets an introduction before their first appearance. It also has sixteen pages of well-chosen photos, endnotes and a bibliography.""-- ""The NYMAS Review"" ""A unique and substantial contribution to the growing number of World War II histories.""-- ""Midwest Book Review"" ""A fascinating anthology which sheds new light on the Bletchley Park story and shows that there is still more to tell.""--Tony Comer OBE, former GCHQ Departmental Historian"