Files mostly consist of correspondence with friends and artists with whom Parsons had a personal relationship, although letters touching upon gallery business are scattered throughout. As close friends, many of the artists shared details about their personal and family life, travels, work, and careers. Gallery artist correspondents include Larry Bigelow, Alexander Calder, and William Condon. Of particular note are letters from Ad Reinhardt discussing his work in relation to the gallery and exhorting Parsons to fight for her (and his) rightful place in history. Another significant and prolific correspondent is the English artist Adge Baker, with whom Parsons had a romantic relationship. The two lived together for several years in the house that Parson purchased shortly after she arrived in Paris in 1923. Although they separated in 1932, they remained life long friends.

Notable friends and other correspondents include heiress and world-class speed boat racer Joe Carstairs, the Marchioness of Dufferin and Ava (Lindy Guinness), art critic Rosalind Constable, and art and literary critic Dale McConathy, who briefly worked for Parsons as a gallery assistant. Personal correspondence also includes Christmas cards, postcards, telegrams, and third party correspondence to gallery employees and Lee Hall, Parsons' biographer and gallery artist. Letter files are arranged alphabetically, postcards are arranged by decade, but Christmas cards are not in any order since it was difficult to determine dates or the full names of the correspondents.

These files reflect how deeply Parsons' life was intertwined with the gallery as correspondence with dealers, museum directors, researchers, collectors, arts organizations, gallery staff, and artists predominate in this subseries, although letters from friends are scattered throughout. Letters address a variety of topics including requests for Parsons to be a jurist for juried exhibitions, exhibitions and sales of her own art work, references for artists, requests for interviews, questions from researchers, and communications from gallery staff. Letters from Jock Truman, include his original cover letter (1961) and updates concerning gallery business (1964, 1966-1968, and 1972).

Letters from Parsons include a letter of introduction for her former husband Schuyler Parsons to Peggy Guggenheim (1965) and a suggestion to collector Paul Mellon (1976)that Barnett Newman's Stations of the Cross belongs in the National Gallery of Art, Washington, D.C.. Parsons response to a researcher (1979) provides her insights concerning the early history of the gallery and her connection with the Abstract Expressionists. Other significant correspondents include Ossip Zadkine (1956), Jacqueline Monnier (1978 and 1982), and Judith Rothschild (1980). Finally, letters that post-date Parsons death in July, 1982 include condolence letters to gallery staff and correspondence between Jack Tilton, her former assistant at the gallery and William Rayner, her nephew and the executer of her estate, to establish prices for her art work.

Files are arranged chronologically by year, followed by a file of undated letters