The opening series consists of four subseries: Papers, Genealogy, Garrison Family, and Friends and Associates.
The Papers subseries includes correspondence, articles, and also inventories regarding Garrison Papers located in other repositories.
The Genealogy subseries includes James Gould's research material gathered while compiling the family trees, Frank Wright Garrison's notes, and the notes and correspondence compiled by Wendell Phillips Garrison in 1884 while attempting to trace the family's early history in New Brunswick, Canada.
The Garrison Family subseries contains information on fifty-two Garrisons and is arranged alphabetically by person. Document types include clippings, pamphlets, datebooks, legal records (wills, birth and marriage certificates), tributes, memorials, biographies, commemorative poems, letters of recommendation, and related correspondence. The largest groups of material relate to WLG 1805 and WLG 1838. Of particular interest are various biographies of WLG 1805, including a handwritten memoir by his son, and documents related to the Francis Todd libel suit brought against Garrison and Benjamin Lundy in 1830; and an incident in 1835 when WLG 1805 barely escaped lynching by a mob in Boston. There is a handwritten autobiographical reminiscence of WLG 1838 dictated to his daughter Agnes in 1909 and correspondence related to his railroad accident in 1871.
The Friends and Associates subseries consists of the same type of materials as subseries three, with the addition of published writings and memorabilia. This subseries contains information on many noted people. Although most of the material included here concerns friends of the Garrisons, there is also information about others that the family collected. Persons covered in this subseries include Susan B. Anthony; Alice Stone Blackwell; Frederick Douglass; Henry George; Thomas Wentworth Higginson; Harriet Martineau; Theodore Parker; Wendell Phillips; Parker Pillsbury; Joseph Lindon Smith; Harriet Tubman; Booker T. Washington; Theodore Dwight Weld; and Marie Zakrzewska. Documents on the McKim family include an autobiographical dairy by James Miller McKim, a cookbook (1831) belonging to Sarah Speakman McKim, and documents related to her separation from the Society of Friends for marrying outside the Society (1840). Also of interest is an 1872 sea diary of Charles Daniel.