This work investigates the extent and operational mechanics of Soviet intelligence infiltration within British institutions during the Cold War. Authors Nigel West, a noted intelligence historian, and Oleg Tsarev, a former KGB officer, synthesize previously classified archival documents to reconstruct the networks of British agents working for the Soviet Union. The text provides a systematic examination of both high-profile defectors and the obscure recruiters who facilitated their activities.

The text is regarded as a significant contribution to the study of Cold War espionage due to its unique access to primary source material from the KGB archives. The collaborative nature of the research provides a balanced, albeit dense, perspective on the mechanics of intelligence gathering and counter-intelligence efforts.