Throughout his career, Diamond kept a personal file in chronological order.

Although the records are found in one long chronological series, several distinct parts exist. The earliest file, dating from 1955 to 1958, primarily contains outgoing messages and personal items on finances, travel arrangements, and publications. It includes information on EDI courses; Diamond's letters to Bank officials during his missions in Ethiopia, Greece, Turkey, and Tunisia; a letter to Newton Parker, March 24, 1958, onthe roles of economic institutions in Honduras; and a memo to S.R. Cope of April 1, 1958, reporting on Davidson Sommers's meeting with a Yugoslav representative on future loans to Yugoslavia.

Records also relate to Diamond's work in India as an advisor to the Industrial Credit and Investment Corporation of India (ICICI). The files between 1958 and 1960 provide a view of the early organization of the ICICI and the establishment of its policies. Items include incoming and outgoing correspondence; meetingnotes; reports; clippings; and personal correspondence. Correspondents include Eugene Black and George D. Woods; ICICI officials; Indian government officials and industrialists; the IBRD resident representatives in India and Pakistan; and various World Bank staff members. Some correspondence discusses the establishment of the Pakistan Industrial Credit and Investment Corporation Limited and developments in Ethiopia.

Overall, the bulk of this series relates to Diamond's assignments at the Bank between 1962 and 1978. For the first eight years, the files contain primarily copies of Diamond's outgoing messages; thereafter the files increasingly include copies of incoming records, such as reports from the field and copies of records sent to him while he was on mission travel. The files from the IFC period contain many records about the development banks in South Asia and North Africa. When Diamond was a Director of country programs in the South Asia Regional Vice-Presidency, the files include records related to the Tarbela Dam project and the efforts to assist Bangladesh. Note that the records in these files are largely duplicates of those in the official files of the Bank, but their chronological arrangement allows the user to see the variety of issues that Diamond was handling and to trace the evolution of Diamond's and the Bank's responses to events.

The final part of the series contains records relating to Diamond's work as a consultant to IFC between 1980 and 1990. The earliest records relate to IFC's role in the work of the Societe Internationale Financiere pour les Investissements et le Developpement en Afrique (SIFIDA), but most of the records relate to the Banco Portugues de Investimento SA (BPI). In 1978 a group of Portuguese industrialists created an "Executive Group" to develop a private financial institution to promote private economic development. They sought the involvement of the IFC, and the IFC engaged Diamond as its consultant on the BPI.