Andreassen's papers fall into three series: personal materials, diaries, and professional files. Personal materials include family correspondence, 1929-ca 1932, and ca 30 cm of class notes and draft papers stemming from his student years, largely at Louisiana State. There are also files of private correspondence, some addressed to Mrs Andreassen, from the period 1975-1980. Andreassen's diaries cover the years 1936-1940, 1945-1952, 1962-1965, and 1968-1976. They record the working day and are interleaved with memoranda and correspondence, often of a personal nature. Professional files vary in nature with each stage of Andreassen's career, but correspondence and reports are consistent elements. To these may be added copies of surveys and inventories of the Louisiana Historical Records Survey, expense accounts and photographs arising from his work for UNRRA, records of archival deposits and drafts on an institutional history prepared as Archivist of CNR, and annual reports written as McGill Archivist.

This file contains copies of Montreal Neurological institute and Montreal Neurological Hospital Annual Reports: 1961-92 through 1970-71 (10 items).

This file contains copies of Montreal Neurological institute and Montreal Neurological Hospital Annual Reports: 1972-73 through 1982-83 (12 items). Two copies of 1978-79.

This file contains a McGill University annual report for 1983-1984. Includes report from principal, financial report, statistics, list of members of administrative and governing bodies, highlights of McGill activities, honours and awards, deaths, and other information.

This file contains annual report of the Montreal Neurological Institute. Includes list of staff and information about research, lectures, finance, and statistics.

This file contains annual report of the Montreal Parks and Playgrounds Association, Incorporated, including Rosemount Community Centre and Community Garden League of Greater Montreal. Includes financial information. Author William Bowie.

This file contains a Montreal Parks and Playgrounds Association annual report from 1964. Includes general information about the Association, the report of the president, the report of the executive director, statistics about attendance at events, and a list of officers and directors. Author Jacques Simard.

This file contains various promotional McGill publications, especially related to the Development and Alumni Relations. Principal's Report, 2008-2009, 2010-2011; McGill Facts, 2005-2006 (2 copies); Building the Future: The History of the Faculty of Engineering at McGill University, 1855-2004; Report on Private Giving, 1995-1996, 2004-2005, 2005-2007, Spring 2008, Spring 2009, Fall 2010, Spring 2011; McGill Extra, Office of Development and Alumni Relations, Fall 2000; Giving in Action - Development Office, June 2001 (3 copies); McGill Journal of Education, Vol. 39, No. 1, Winter 2004; Explore the World, Deluxe Travel Tours, University of Toronto, 2000; McGill Milestones, 1744-1999 - McGill Development Office; Les Grandes Dates de L'Histoires de McGill, 1744-1999; Macdonald Library and Learning Centre brochure (6 copies); Bibliothèque et centre d'apprentissage de Macdonald (2 copies); The Cupola, Fall 1994; McGill University and China: Building Partnerships Across the Pacific, 2011-2012 (2 copies).

This file contains a McGill University annual report for 1983-1984. Includes report from principal, statistics, information about fundraising, highlights of McGill activities, list of members of administrative and governing bodies, honours and awards, deaths, financial report, and other information.

This file contains a McGill University annual report for 1988-1989. Includes information about fundraising, highlights of McGill activities, list of members of administrative and governing bodies, statistics, honours and awards, deaths, a financial report, and other information.