This lengthy report was State Department Bureau of Intelligence and Research's contribution to the first National Intelligence Estimate on the nuclear proliferation, NIE 100-6-57. Written at a time when the United States, the Soviet Union, and the United Kingdom were the only nuclear weapons states, the “Fourth Country” problem referred to the probability that some unspecified country, whether France or China, was likely to be the next nuclear weapons state. Enclosed with letter from Helmut Sonnenfeldt, Division of Research for USSR and Western Europe, to Roger Mateson, 4 June 1957, Secret

This document provides an overview of the London Nuclear Suppliers' Meeting which included the addition of the five newest countries to the original seven. Most old and new members were receptive when Washington lobbied them to support a “long term and stable regime of restraint” on the export of sensitive enrichment and reprocessing technology. While the French were supportive of the moratorium proposal, the Germans were uncomfortable with it, not least because of the implications for their deal with Brazil.

The UN inspection team for the supervision of the dismantling of the Soviet bases was to be made up of representatives from Sweden, Mexico and Switzerland. Switzerland feels uncomfortable with being included in the mandate, due to their representation of American interests in Cuba.

The Chinese Embassy in Sweden summarizes the reaction in the local press to the coup in South Korea.

In this entry, Mitrokhin draws upon KGB sources to describe Yuri Velichkov Bagomil Stanimerov (b.1941), a Bulgarian citizen who graduated from the Moscow State Institute of International Relations in 1968. Stanimerov was recruited by the Bulgarian branch of the KGB in 1970, and became a resident of Sweden in 1972. Mitrokhin’s summary of KGB documents indicates that in April 1974, CIA officer Huey Walter “Hearst” made Stanimerov an offer in the name of the National Security Council. While Stanimerov refused the offer, he told Hearst that he would continue collaborating with him. Stanimerov subsequently traveled to many foreign countries, but the Americans no longer expressed interest in him.

In 1975, Stanimerov was sent to work in the Bulgarian embassy in the United States. The Americans began to train Stanimerov as a spy and tried to ideologically convert him. The Mitrokhin account posits that the KGB gave Stanimerov instructions in case the latter succeeded in infiltrating the CIA. In 1978, the KGB received information regarding the fact that Stanimerov was being investigated by the FBI for his ties with the Bulgarian intelligence services