Series 1, Institute of Pacific Relations Records, 1938-1961, consists of minutes, meeting and financial records, and papers documenting the general purpose and workings of the American IPR (formerly the American Council of the IPR). These papers reflect the evolution of the IPR, including its near-merger with other like-minded organizations in 1947, its output of publications such as the Far Eastern Survey and its involvement in regional, national and international conferences. Lockwood's involvement in the IPR, first as Executive Secretary and later as member of the Board of Trustees, is documented, along with his work to maintain interest in the IPR and its materials among members and to build contacts for the IPR in the New York and Washington, D.C. areas. In 1943 Lockwood took a leave of absence as the IPR's Executive Secretary to direct a series of studies for the US Department of State Office of Foreign Relief and Rehabilitation Operation. The resulting publication, Studies of Relief and Rehabilitation in China, is included here.

This series also contains correspondence that documents the concerns of IPR members, including William Lockwood, when the IPR was accused of being a Communist front organization. It was a widely held though apparently erroneous assumption that the IPR was on the Attorney General's list of subversive organizations. By 1948, then Executive Secretary Clayton Lane was making it clear in letters to members that the IPR was in danger of losing funding from businesses and banks because of its reputation. In 1947 IPR member Alfred Kohlberg had begun a campaign against the IPR, accusing the organization of bias in regards to the Far East, particularly China. Of particular interest is the correspondence among members surrounding the April 22, 1947 meeting in which Kohlberg asked for proxies to authorize himself to appoint a committee to investigate his charges. (He was subsequently turned down, and resigned as a member of the IPR). Also of interest is Kohlberg's letter of April 30, 1948 in which he alleged that certain IPR members had a "high opinion of Chinese Communists". He also took issue with the formation of the Far Eastern Association, founded by members of the IPR, which was devoted to culture and history rather than current affairs. In 1947, a Federal Grand Jury had indicted several members of the IPR, and a House Committee on Un-American Activities investigation of the IPR was feared. In light of this situation, Kohlberg, in his letter, insinuated that the Far Eastern Association had been founded as a "back-up" organization with a clean record in preparation for the possible fall of the IPR.

Information concerning the investigation of the IPR by the Senate Judiciary Subcommittee on Internal Security and the House Committee on Un-American Activities can be found in Series 1 in correspondence as well as in testimony and published newspaper and magazine reports of the time. Although there are no documents pertaining directly to the 1942 letter authored by Lockwood that was among the papers seized by McCarran, there is correspondence devoted to the surrounding figures and issues in the Amerasia case. There is correspondence and other material regarding Owen Lattimore and Philip Jessup, who essentially served as links to McCarthy's and McCarran's investigations of the IPR. The principal charge against the IPR was that Jessup, as a trustee of the IPR, accepted money from a fund controlled by Frederick Field (an alleged Communist and member of the IPR Executive Committee), in return for which he committed the Far Eastern Survey to the Communist line. McCarthy attempted to link Lattimore, one-time head of the IPR's Research Advisory Committee and former member of Amerasia's editorial board, with the theft of government documents. This series also documents the IPR's tax exemption case. Of particular interest with regard to this case is the report on the trial, the verdict, and the letters, mainly from the IPR's then Secretary General William Holland, advising IPR members on testimony.

The correspondence consists primarily of letters of encouragement and testimonials from IPR supporters, although there is a small portion of correspondence between Lockwood and David Rowe, who testified against him during the hearings, and Harold Erdman, who attacked him in the press. Both men were affiliated with Princeton. The correspondence also contains letters between IPR members, discussing the situation and refuting charges, as well as letters from Lockwood and others to editors of prominent newspapers and magazines. Of particular interest is a letter from the IPR's legal counsel to Senator McCarran (Box 3, Folder 4), demanding the return of illegally seized documents to the IPR and also recommending that the Senator contact William Lockwood for testimony. Two signed letters from McCarran to Lockwood, one acknowledging Lockwood's request for copies of the hearings and one in which McCarran presents Lockwood with a subpoena for testimony are included here. Also contained in the correspondence are copies of letters to Senator McCarran from Lockwood and others. Statements and testimony of prominent IPR members, including William Lockwood, are also contained in this series.