For a hundred years, GCHQ – Government Communications Headquarters – has been at the forefront of innovation in national security and British secret statecraft. Famed for its codebreaking achievements during the Second World War, and essential to the Allied victory, GCHQ also held a critical role in both the Falklands War and Cold War. Today, amidst the growing threats of terrorism and online crime, GCHQ continues to be the UK's leading intelligence, security and cyber agency, and a powerful tool of the British state.

Written by intelligence and security expert Professor John Ferris with access to our historic archives, the book strips away secrecy to an unprecedented level giving readers an insight into how GCHQ has helped to shape world events.

Behind the Enigma covers our origins in World War One, through to Bletchley Park and World War Two, to the present day. The book offers a unique insight into major international moments of the last century – including the retreat from empire, the Cold War and the Falklands – which only become fully explicable in the light of the secret intelligence record.

The book also explores who cryptanalysts really are and how they think and act, including stories of the people from our past and how they contributed national security.