A fascinating and unique history of the launch of Britain's Secret Intelligence Service through the unusual life of its founder, Mansfield Cumming.

• Sir Mansfield Cumming, the founder of the British Secret Service and the original 'C', has until now been a shadowy figure. For this authorised biography, the Secret Intelligence Service has released to Alan Judd, Cumming's voluminous diaries, which have never been seen outside the Service and will be put back into storage in perpetuity when Judd has used them.
• The result is likely to be the most sensational biography of the season, and the definitive account of how MI5 and MI6 - the models for all subsequent secret services all over the world - were set up.
• Cumming signed himself 'C', was referred to as such in Whitehall and always used green ink, traditions maintained to this day. His life not only makes riveting reading but casts fascinating light on the development of the Secret Service and its influence on the twentieth century.