Arranged in nine series: Series 1: Attorney General Office Files, 1962-1966; Series 2: Senatorial Papers, 1965-1978; Series 3: Speeches and Writings File, 1961-1980; Series 4: Campaign Materials, 1960-1978; Series 5: Political File, 1963-1978; Series 6: Legal File, 1979-1988; Series 7: Miscellany, 1956-1988; Series 8: Oversize, 1966-1973; and Series 9: Classified, 1974.

Summary of the contents: Correspondence, memoranda, writings, speeches, transcripts of interviews, reports, notes, subject files, draft and printed legislative bills, briefing books, press releases, photographs, and other papers relating primarily to Brooke's career as attorney general of Massachusetts (1963-1966) and as U.S. senator (1967-1978). Brooke's cases as attorney general pertain to conflict of interest, consumer protection, corruption, eminent domain, and the case against Albert De Salvo, known as the Boston Strangler. His chief interest as senator concerned such domestic issues as housing, the aged, and poverty.

Arranged in three parts in twenty-two series.
Part I arranged in fifteen series. Series 1: Massachusetts Files, circa 1780-1983; Series 2: Under Secretary of State Files, 1963-1970; Series 3: Department of Health, Education, and Welfare Files, 1953-1973; Series 4: Secretary of Defense Files, 1972-1973; Series 5: Attorney General Files, 1969-1974; Series 6: Woodrow Wilson International Center for Scholars, 1973-1975; Series 7: Ambassadorial File: Great Britain, 1974-1976; Series 8: Secretary of Commerce Files, 1974-1984; Series 9: Ambassador at Large: Law of the Sea Files, 1977-1980; Series 10: Milbank, Tweed, Hadley & McCloy Files, 1980-1984; Series 11: Senate Campaign Files, 1974-1984; Series 12: Classified; Series 13: Top Secret; Series 14: Restricted Data; and Series 15: Oversize, 1956-1973.
Part II arranged in one series. Series 1: Milbank, Tweed, Hadley & McCloy Files, 1977-1991.
Part III arranged in seven series. Series 1: Massachusetts File, 1946-1969; Series 2: Alphabetical File, 1971-1999; Series 3: Correspondence File, 1980-1999; Series 4: Organizations File, 1975-1999; Series 5: Speeches and Writings, 1963-1999; Series 6: Classified, 1969-1994; and Series 7: Digital File, 1994. Contains correspondence between Elliot Richardson and Senator Edward Brooke.