The is a massive collection of handwritten notes and summaries compiled by Vasili Mitrokhin , a senior KGB archivist who defected to the United Kingdom in 1992. Often described as the "greatest single cache of intelligence ever received by the West," these files expose Soviet espionage and active measures spanning from the 1930s to the 1980s. Finding and Accessing the Archive (PDF & Print)
: For academic research, you can view typed versions of the files at Churchill College, Cambridge by appointment. Major Historical Revelations mitrokhin archive pdf