This series consists of Marian Lawrence Peabody's correspondence with her parents, Bishop William Lawrence and Julia Cunningham Lawrence; her maternal grandmother and godmother, Sarah Parker Cunningham; her aunts Harriet Lawrence Hemenway, Susan Lawrence Loring, and Hetty Lawrence Cunningham; her siblings Julia "Julie" Lawrence (Fearey), Sarah "Sallie" Lawrence (Slattery), Ruth "Ruthie" Lawrence (Reed), Eleanor "Elsie" Lawrence Mills, William Appleton "Appie" Lawrence, and Frederic "Freddie" C. Lawrence.

A small amount of correspondence with her husband Harold Peabody, largely written after 1934 when the couple began to live apart, illustrates Marian's long-lasting but difficult marriage. Marian's extensive correspondence with her daughter, Gertrude Peabody (McCue), begins in 1921. Later correspondence includes that with her grandchildren William McCue and Marian McCue, as well as with many nieces and nephews. Many family letters, particularly those from her mother, sisters, and daughter, are undated.

Topics largely consist of news of Marian's extended family including courtships, weddings, births, childrearing, illnesses, and deaths, as well as descriptions of travel to Europe, Scandinavia, and the western United States. There is also much correspondence between Marian and her siblings after the death of their father in 1941, concerning memorials, distribution of his papers and portraits, the publication of his biography, and financial matters. Letters from her daughter in the 1940s discuss Gertrude's hospital social work during World War II, as well as marriage and motherhood.

Marian Lawrence Peabody's early personal correspondence was with childhood friends and schoolmates, including Theresa "Tradja" Davis, Marian Mason, and Carrie Dabney. Many of her friends traveled extensively and wrote descriptive letters during extended trips to Europe, Bolivia, and Shanghai. One such friend was Gertrude Codman Parker Carter (1875-1953), who married Sir Gilbert Thomas Carter, governor and commander-in-chief of the Bahamas, later the governor of Barbados and administrator of Trinidad and Tobago. Gertrude often illustrated her letters with detailed drawings and descriptions of people and places in these lands.

Marian also maintained a long correspondence with Alice Vanderbilt Morris (1874-1950) of New York, the wife of Dave Hennan Morris, later the American ambassador to Belgium. Known to her friends as "Angela," she and her family founded the International Auxiliary Language Assoc. of which Marian was a director. John D. Rockefeller, Marian's Mt. Desert Island neighbor, began corresponding with Marian in 1929 about their mutual interest in insomnia treatments. At first opposing each other on the development of roads on Mt. Desert Island and Acadia National Park, they became longtime friends.

A large portion of Marian's personal correspondence reflects her involvement with charities and social work. Letters to Marian requesting charity first appear in 1894. Her interest in the Lawrence Boys' Club at the North Bennet Street School prompted a ongoing correspondence with many of the Irish and Italian boys, some of which continued throughout her life. Similarly, many sailors Marian met through her work at Sailors' Haven, an Episcopal Church mission at the port of Boston, maintained a lifelong correspondence with her, among them John M. Fournier, Tom Foley, and John and Mabel Creber. Other 1904-1905 correspondence is with Sailor's Haven superintendent Stanton King and architect Charles Collins in her capacity as head of the Sailors' Haven building committee to construct a new facility for visiting sailors. Later correspondence reflects Marian's work with the U. S. Social Hygiene Board, the Massachusetts Eye and Ear Infirmary, and the Bar Harbor chapter of the American Red Cross.

Beginning in 1922, letters from Austen Riggs Foundation doctors discuss treatments for Marian's anxiety and stress. Correspondence (including third party) related to building roads on Mt. Desert Island, Maine, and the development of Acadia National Park includes a 1930 letter from Frederic Law Olmsted addressing the issue. Many letters contain birthday congratulations, condolences for the fire that destroyed her Bar Harbor home in 1947, and sympathies upon the death of her husband, Harold, in 1961. A large amount of later correspondence consists of letters related to the publication of Marian's articles and later her diary, including letters with publishers, the typist who transcribes her diaries, and many letters of congratulation after her book's publication in 1967. Letters of 1967 and 1968 consist almost entirely of "fan mail."

The diaries of Marian Lawrence Peabody span the years 1887 to 1965, reflecting her thoughts and activities and those of her family and friends. Much more introspective than her letters, her entries dwell on her illnesses, relationships, angst over remaining single through her twenties, the emotional stress of her marital difficulties, and other personal insights. There are no entries from the date of her marriage in May 1906 until 1909, although Marian attempted to fill in some of the missing entries, most likely in 1908.

Highlights from her earlier diaries include descriptions of the Chicago World's Fair in 1893, watching John Singer Sargent paint a portrait of her uncle (Feb. and March 1903), meeting Theodore Roosevelt and Henry Wadsworth Longfellow, and a description of the Kronprincessin Cecile with wealthy passengers and their gold bullion docking at the neutral port of Bar Harbor in 1914. Marian also describes her travels to Europe in 1896, 1901, 1902, 1903, 1910, 1925-1926, 1932, and 1938; to Scandinavia in 1913; and to California and the western United States in 1901 and 1923.

Later diaries describe Marian's activities raising money and running the social work programs of the YWCA during World War I, and as the only woman on War Committee for New England. She describes her daughter's childhood and Gertrude's activities as head of social work at Cushing Hospital in Framingham during World War II under the Red Cross. Except for the World War II years, there are few mentions of current events throughout the diaries, although she occasionally comments on local and national politics during her later years.

Items removed from the diaries consist largely of invitations, concert and theatre programs, and printed materials related to her interests in art and charitable work. The bulk consists of newspaper clippings related to family or current events, particularly World War II.

Marian published excerpts from her early diaries (1887 to 1905) in 1967 as To Be Young Was Very Heaven: A Boston Girlhood at the Century's Turn from the Diaries of Marian Lawrence Peabody.

This series contains the family and personal correspondence and personal papers of the interrelated Lawrence and Peabody families. Much of this material appears to have been sent to Marian Lawrence Peabody for her perusal or collected by her as significant keepsakes. Included are the diaries of Marian's aunt, Hetty Lawrence Cunningham.

For correspondence between the Lawrence and Peabody families and Marian Lawrence Peabody, see Series I, Family Correspondence.

This series contains printed material related to the 1901 Episcopal Convention, the 1902 coronation of King Edward VII, Sailor’s Haven, the Lawrence Century Club, the War Work Council of the YWCA, the Bar Harbor branch of the Red Cross, and Acadia National Park. Also included are wedding invitations and announcements, report cards, theatre and concert programs, memorials and obituaries, postcards, church bulletins, greeting cards, and newspaper clippings related to Bishop William Lawrence and other family members.

Material added to the Marian Lawrence Peabody papers in February 2015 includes Marian's personal correspondence, largely related to the publication of her diary in 1967, as well as personal papers, writings, and printed material.