This detailed 800 page book covers fifty years of MI6, the UK’s foreign espionage service. From relatively humble beginnings during the second world war, MI6 grew to become a leading foe of Soviet Russia and its notorious KGB. The book documents in detail issues that affected the service from the beginning and I especially was enamoured by the division of early chapters covering each of the spheres of influence where MI6 were working in the aftermath of World War 2. The book amalgamates knowledge I have of this service from other reading and often due to its sheer volume, will analyse in depth details that were previously unknown. It often is critical of the service’s failures and sometimes questionable morality in its operations. The obvious exposure of the country by moles within MI6 such as Kim Philby were very damaging to our nation. It is clear that there was much frustration during the Cold War with a failure to penetrate the Soviet system properly. Also, as the years have moved on, the critical importance of US intelligence – the CIA and NSA – to UK intelligence services – becomes paramount. Our declining empire has meant that MI6 has had to do all it can to keep our position as a global power propped up in the world. There is a very good section on the often blunderous years of operations in the Middle East, culminating in the Suez crisis which was a clear debacle. Moving into the modern era (Book concludes just before second Gulf War) the author successfully identifies future directions for the service and there is interesting coverage of MI6 whistleblower Richard Tomlinson, who has revealed his life as an operative in a controversial book. I enjoyed this large book and feel that it will be useful for reference in any further research I may do on intelligence services.