This series provides a rather fragmentary overview of Katharine Brand's career and private life. Entries for biographical directories and newspaper clippings outline the bare bones of her career, and transcripts of interviews with a co-worker and family flesh it out, as well as providing anecdotal personal information. Her autobiographical writings provide some insight into the emotional life of her childhood and adolescence. Information here about her time at Smith College and at Katharine Gibbs School is very sparse and fragmentary. There are personal documents like address books and passports, as well as papers relating to her voluntary activities, especially with the Friends of the Library, Vienna, Virginia. The family information is exclusively about her father, Charles Brand, and his parents and siblings, except for material related to her mother's death and the genealogical material which is primarily about her mother's side of the family. Of note are a few writings about reform issues by her grandmother, Juliet Brand, and information about the family's connections with Oberlin College.

This series is organized into two subseries: Family and Friends and associates. Brand filed her correspondence with biographical materials about, and writings by, many of the individuals, and her organization has been maintained, with the additional items interspersed chronologically with the correspondence. Brand's cousin, Phebe Adams, who was the interim caretaker of the papers, sent portions of the correspondence to family and friends, so for instance, an extensive run of letters between Brand and one of her cousins is missing from these papers.

Much of the correspondence is rather sparse and consists primarily of incoming letters. The major exceptions are correspondence between Brand and the Adams branch of her family, and Ray Stannard Baker, both of which contain some outgoing letters from Brand. Besides Baker, other notable correspondents include: Jessie Baker, Millicent Todd Bingham, Josephus Daniels, Arthur Link, David Morton, and Ishbel Ross. The Baker correspondence, along with letters between Brand and colleagues during and after her time at the Library of Congress, provide an in depth look at Brand as a professional; and correspondence with the Adams branch of her family reveals her role in her extended family. There are a few folders of correspondence between Charles Brand and family members other than Katharine.

Brand's diaries from her youth, her years in Amherst, and her travels, make up the bulk of this series. The first two diaries are in a reflective narrative form that reveals Brand's thoughts and emotions, while the travel diaries tend to be terse, of the line-a-day variety. This series also contains drafts and final versions of Brand's articles and other writings such as letters to the editor. There are several folders of correspondence about various writing projects. In addition, there are a few examples of Charles Brand's writings saved by Katharine.

The bulk of the papers in this series relate to Brand's multi-faceted employment with Ray Stannard Baker as he wrote his biography of Woodrow Wilson, and later in the Division of Manuscripts of the Library of Congress. It is divided into two subseries. Library of Congress contains records of Brand's employment there, from her years as "special custodian," to her official employment as Assistant in, and finally Head of the Division of Manuscripts, from 1939 to 1956. In the latter position, she continued to be the resident expert on the Wilson Papers, but was also in charge of all of the twentieth century manuscript collections in the Division. Subjects and organizations includes documents related to her long involvement as employee and friend of Baker (1925 until his death in 1946), as well as custodian of his and Wilson's papers. This subseries also consists of her pre- and post-retirement participation in Woodrow Wilson-related organizations.

This series contains a large number of photographs of Brand alone, with family and friends, and with colleagues at the Library of Congress; her family and other individuals; and family homes and other places. There are images from her childhood through the 1960s. The series includes photographs of friends and associates, from Smith College classmates to portraits of Ray Stannard and Jessie Baker, Millicent Bingham, and other notable friends and associates. There are also a few images of Woodrow Wilson and his first and second wives, Ellen Axson and Edith Bolling.