Fully Updated Centenary Edition

GCHQ is the largest and most secretive intelligence organisation in the UK, and has existed for 100 years - but we still know next to nothing about it.

In this ground-breaking book - the first and most definitive history of the organisation ever published - intelligence expert Richard Aldrich traces GCHQ's development from a wartime code-breaking operation based in the Bedfordshire countryside into one of the world-leading espionage organisations.

Packed with dramatic spy stories, GCHQ also explores the organisation's role behind the most alarming headlines of our time, from fighting ISIS to cyber-terrorism, from the surveillance state to Russian hacking.

Revelatory, brilliantly written and fully updated, this is the crucial missing link in Britain's intelligence history.