Operation PBHistory was a covert operation carried out in Guatemala by the United States Central Intelligence Agency (CIA). It followed Operation PBSuccess, which led to the overthrow of Guatemalan President Jacobo Árbenz in June 1954 and ended the Guatemalan Revolution. PBHistory attempted to use documents left behind by Árbenz's government and by organizations related to the communist Guatemalan Party of Labor to demonstrate that the Guatemalan government had been under the influence of the Soviet Union, and to use those documents to obtain further intelligence that would be useful to US intelligence agencies. It was an effort to justify the overthrow of the elected Guatemalan government in response to the negative international reactions to PBSuccess. The CIA also hoped to improve its intelligence resources about communist parties in Latin America, a subject on which it had little information.

The first phase of the operation began soon after Árbenz's resignation on June 27, 1954: several agents were dispatched to Guatemala beginning on July 4. These included agents of the CIA and the Office of Intelligence Research (OIR). The first phase involved the collection of 150,000 documents from sources including Árbenz's personal possessions, trade union offices, and police agencies. The ruling military junta led by Carlos Castillo Armas aided these efforts. Following a presentation made to US President Dwight Eisenhower on July 20, a decision was taken to accelerate the operation, and the number of people working in Guatemala was increased. The new team members posed as unaffiliated with the US government to maintain plausible deniability. The operation helped set up the Guatemalan National Committee of Defense Against Communism, which was covertly funded by the CIA: agents of the committee became involved in PBHistory. The team studied over 500,000 documents in total, and finished processing documents on September 28, 1954.

PBHistory documents were used to support the CIA's existing operations Kufire and Kugown, which sought to track Latin American communists and to disseminate information critical of the Árbenz government. Documents were also shared with the Kersten Committee of the US House of Representatives, which publicized PBHistory within the US. The documents uncovered by the operation proved useful to the Guatemalan intelligence agencies, enabling the creation of a register of suspected communists. Operation PBHistory did not succeed in its chief objective of finding evidence that the Guatemalan communists were being controlled by the Soviet government, and was unable to counter the international narrative that the United States had toppled the government of Jacobo Árbenz to serve the interests of the United Fruit Company.

The October Revolution of 1945 in Guatemala led to the election of Juan José Arévalo as President of Guatemala, who initiated reforms based on liberal capitalism. Arévalo was an anti-communist, and cracked down on the communist Guatemalan Party of Labor (Partido Guatemalteco del Trabajo, PGT). The US government was nonetheless suspicious that he was under the influence of the Soviet Union. Arévalo's defense minister Jacobo Árbenz was elected president in 1950. Influenced partly by McCarthyism, the US government was predisposed to see communist influence in Árbenz's government, particularly after the legalization of the PGT. Árbenz also had personal ties to some PGT members. In 1952 Árbenz began an agrarian reform program that transferred uncultivated land from large landowners to poor laborers in return for compensation. In response the US-based United Fruit Company, which had large landholdings in Guatemala, intensively lobbied the US government for Árbenz's overthrow.

US President Dwight Eisenhower authorized a Central Intelligence Agency (CIA) operation to overthrow Árbenz, code-named Operation PBSuccess in August 1953. Within the CIA, the operation was headed by Frank Wisner, who had worked in the US intelligence services since World War II. While preparations for Operation PBSuccess were underway, the US government issued a series of statements denouncing the Guatemalan government, alleging that it had been infiltrated by communists. On June 18, 1954 Carlos Castillo Armas, a Guatemalan army Colonel in exile since a failed coup in 1949, led an invasion force of 480 men into Guatemala. The invasion was supported by a campaign of psychological warfare, which presented Castillo Armas's victory as a fait accompli to the Guatemalan people. Worried by the possibility of a US invasion, the Guatemalan army refused to fight, and on June 27 Árbenz resigned.

The actions of the United States resulted in international outrage. Media outlets across the world accused the US of sponsoring a coup to reverse Árbenz's agrarian reform in the interests of the United Fruit Company. This criticism was influenced by the coverage put out by media outlets in communist-controlled countries, but was repeated in the media in countries that were US allies, with Britain's Labour Party and the Swedish Social Democratic Party joining in. Latin American opposition to the US reached a new peak: author Daniel James stated that "No one could recall so intense and universal a wave of anti-US sentiment in the entire history of Latin America." Although people within the US saw the coup as a triumph for US foreign policy, CIA officials felt that in order for Operation PBSuccess to be termed a success, further action was needed. Thus, the CIA was interested in finding documents that would allow it to portray the administration of Árbenz as being controlled by Soviet communists, and thus to justify the coup.

Due to the quick overthrow of the Árbenz government, the CIA believed that the government and the PGT leaders would not have been able to destroy any incriminating documents, and that these could be analyzed to demonstrate Árbenz's supposed ties to the Soviet Union. According to historian Nick Cullather, Wisner hoped to "expose Soviet machinations throughout the hemisphere". The CIA also believed that it could better understand the workings of Latin American communist parties, on which subject the CIA had very little information. Although there had been an active communist movement in Latin America since 1919, it had largely been clandestine, and the CIA knew little about the methods that parties like the PGT used. The CIA hoped that PGT records left behind in haste would enable its international Communism Division to reconstruct the party's leadership and organizational structure, and possibly do the same for other communist parties in the region.

The CIA also hoped to exploit the aftermath of the coup to bolster its own intelligence resources. Wisner, who was serving as Deputy Director for Plans at the time of the coup, hoped to recruit agents both from among communists who wanted to defect, and from other Guatemalans who might become a part of the new government. In Wisner's words, he wished to identify "people who can be controlled and exploited to further US policy". Furthermore, the agency hoped to use the findings of the operation to demonstrate the extent of Soviet influence for propaganda purposes, and also to use the information gathered to eliminate any communist influence in Guatemala.