In 1928, Wilma Frances Minor, a television interviewer and writer from California, presented Sedgwick with the opportunity to publish the story of a love affair between Abraham Lincoln and Ann Rutledge, based on "original" love letters. Minor entrusted Sedgwick with the letters, from which she planned to write a book serialized in the Atlantic Monthly. Upon publication of the first installment, Lincoln experts questioned the authenticity of the letters. Work on the novel continued while Sedgwick contracted with California detective J. B. Armstrong to research the case. Teresa S. Fitzpatrick of the Atlantic Monthly staff was responsible for supervising the investigation. The letters were proven by experts to be forgeries, and in June 1929, Minor and her mother confessed to having created them. Minor claimed her mother was a psychic and that the spirits of Lincoln and Rutledge had urged her to make their story known.

This subseries is divided into three sections. Carton 13 contains Minor's correspondence with Sedgwick and his staff, as well as their correspondence with others regarding the authenticity of the letters. Sedgwick retained the forgeries, which are filed in Carton 13, along with drafts of Minor's manuscript. Correspondence and reports filed by Armstrong, the detective, and correspondence with Paul Angle, president of the Lincoln Centennial Association, are also located in Carton 13. Cartons 13 and 14 contain comments and inquiries about the story and Sedgwick's research on the letters.

Correspondents of note include Worthington Ford, Wayland A. Morrison, Ida Tarbell, Charles T. and William A. White. Also included is correspondence with representatives from Rumford Press and Little, Brown & Co. regarding publication of Minor's book.

This subseries contains letters, newspaper clippings, and comments on an open-letter debate between Alfred E. Smith and Charles C. Marshall printed in the Atlantic Monthly in 1927. Included are six parts: general correspondence, Charles C. Marshall correspondence, Alfred E. Smith correspondence, miscellaneous, publicity, and comments.

Charles C. Marshall, a New York attorney, wrote to Smith in 1927 challenging Smith's candidacy as a Democratic nominee for president of the United States. Marshall charged that Smith, a Catholic, would have a conflict of interest which would impede his ability to fulfill the oath of office. Marshall's letter was printed by the Atlantic Monthly, which then became a forum for the controversy raised over a Roman Catholic running for president. Notable correspondents on this issue included Bernard M. Baruch, Felix Frankfurter, Edmund F. Gibbons (the Bishop of Albany), Christian A. Herter, Judge Joseph M. Proskauer, Franklin D. Roosevelt, and Lillian D. Wald.

This subseries consists of one carton of materials related to Sedgwick's interest in the Spanish Civil War, his trip to meet with General Francisco Franco in 1937, and articles written on the war. The correspondence is divided into seven parts, with separate files for Juan de Cardenas, the Spanish Consul; Winthrop Carter, whose son was missing in Spain in 1938; and the Marquis del Moral. Included is general correspondence and material related to trip arrangements. Comments about Sedgwick's politics and his articles were divided into pros and cons. Correspondents include J. Roscoe Drummond, John H. Finley, J. D. M. Ford, W. Cameron Forbes, John A. Gade, and Sumner Welles.

This subseries consists of material related to the publication of Opal Whiteley's book, The Story of Opal, which was serialized in the Atlantic Monthly from March to August 1920 and published later that year by G. P. Putnam's Sons. The story appealed to many people, but provoked questions about the diary's authenticity. Whiteley claimed to be the daughter of Prince Henri D'Orleans, allegedly raised by foster parents in an Oregon lumber camp. Belief in her story was widespread, and she was recognized by her late father's mother, the Duchess de Chartres. Whiteley adopted the family name, calling herself Francoise d'Orleans. She toured India as a princess of that country (where she had lived as a small child with her "real" parents) and was an honored guest of that country's noble families.

Sedgwick spent years corresponding with people who knew Whiteley to verify her story, but never renounced its authenticity. His most extensive correspondence was with Whiteley and Elbert Bede, publisher of Oregon's Cottage Grove Sentinel. Bede was his primary research associate on the project.

Sedgwick's correspondence with Whiteley, Bede, and others about Whiteley's unusual childhood is located in Carton 16. Cartons 16 and 17 contain comments from Atlantic Monthly readers. Other materials in Carton 17 include correspondence between Sedgwick and Barbara Ward of The Economist about a fund established to aid Whiteley, who spent her last years in a mental institution; correspondence with G. P. Putnam's Sons, 1920-1921; correspondence with lawyers of Vanity Fair in 1920; drafts of The Story of Opal; miscellaneous notes regarding the manuscript; notes on Whiteley's biography; and assorted printed materials, including newspaper clippings.

This subseries includes correspondence, notes, reports, and committee resolutions, apparently kept by Marjorie Russell Sedgwick, who was appointed to the Committee to Visit the Arnold Arboretum by the Harvard Board of Overseers. The Arboretum, established in Jamaica Plain, Mass. in 1880 as a 500-acre park, became Harvard's botanical gardens. The park is administered by Harvard University and the Boston Department of Parks and Recreation.

Mrs. Sedgwick served during a tense period. In 1953, the corporation which had been founded to raise money for the arboretum challenged Harvard University for control. Included are letters from Mrs. Sedgwick and her husband, as well as "A Survey of the Controversy," by Professor Karl Sax.

This subseries documents Ellery Sedgwick's tenure as trustee of the Boston Public Library. Cartons 20 and 21 contain correspondence and library reports from Milton E. Lord, director of the library. Other significant correspondents include Frank W. Buxton; Wallace B. Donham, dean of the Harvard Business School; Cardinal William O'Connell; John J. Hall, Esquire; and Louis E. Kirstein of Filene's. The subseries also contains reports of the library's Examining Committee, comptroller's reports, budget estimates, personnel reports and staff exams, reports of the Board of Director's meetings, and accountants' reports from the estate of Josiah H. Benton, one of the library's benefactors.

This subseries contains correspondence and reports during Sedgwick's tenure on Harvard University's Board of Overseers and as a member of the Committee on the Classics. Sedgwick was also involved in the university's tercentenary celebration, the reunion of the Class of 1894, and the 1938 Nieman Fellowship awards. The bulk of the correspondence is with other members of the board and the Committee on the Classics, including Philip R. Allen, John Nicholas Brown, W. S. Ferguson, Jerome D. Green, Fred B. Lund, Lewis Perry, W. K. Richardson, George S. Stevenson, Winthrop H. Wade, James P. Warburg, and Charles Warren.

Carton 21 contains Board of Overseers records, general correspondence, and anniversary materials. Cartons 21 and 22 contain correspondence regarding classics at Harvard and class reunions. Carton 22 also contains fellowship awards papers and printed materials.

This subseries consists of correspondence, sales earnings reports, financial statements, and reports for stockholders for Rumford Press of New Hampshire. Sedgwick joined the board of directors in 1918 and was the company's first vice president. He became particularly active in the management of the company, which printed Reader's Digest and the Atlantic Monthly, after his retirement in 1939. Important topics of correspondence include the death of R. P. Weston, company president; the hiring of John G. Gerken as his replacement; and subsequent management problems. His primary correspondents were company presidents John G. Gerken and R. P. Weston and New Hampshire Senator George H. Moses.

Carton 22 contains chronological correspondence files for Gerken, Weston, and Moses. Carton 23 contains general correspondence, correspondence/financial statements, sales and earnings/balance sheets, and prospects (potential printing jobs). Carton 23 also contains correspondence and reports concerning stockholders.

This subseries contains miscellaneous papers related to trustees and alumni of the Groton School of Groton, Mass., of which Sedgwick was both. He graduated from Groton in 1890, taught there from 1895-1896, and served as trustee from 1909 to 1940. This file contains correspondence from 1944 only. Correspondents include John Crocker and Pierre Jay.

This subseries consists of manuscripts submitted to Sedgwick as an assistant editor at the Youth's Companion, where he worked from 1896 to 1900. Correspondents include Eben C. Lamson and George S. Boutwell.