Includes 312 autograph letters signed and initialed and one typed letter signed to and from Delia Bacon and others; 10 miscellaneous items including prospectuses of Delia Bacon, her The author's apology and claim, [1857?], an engraving of Leonard Bacon, a memorandum of an agreement between Delia Bacon and Samuel Coleman, an inventory of school items to be sold at a private sale in 1831 and payments to various people for sums due, and 3 newspaper clippings.

Delia Salter Bacon is the originator of the Baconian theory, which she first proposed in "William Shakespeare and His Plays: An Inquiry Concerning Them," Putnam's Monthly Magazine VII (January 1856): 1-19, and shortly thereafter in The Philosophy of the Plays of Shakspere Unfolded, By Delia Bacon, With a Preface by Nathaniel Hawthorne, Author of "The Scarlet Letter," etc. (London and Boston, 1857). The letters to and from Ralph Waldo Emerson and Nathaniel Hawthorne, in particular, dating from 1853-1856, discuss her research in England on the authorship of Shakespeare's works. In Folger MS Y.c.2599 (48), March 7, [1837], Delia Bacon writes of revising her play, later published as The Bride of Fort Edward (New York: Samuel Colman, 1839), for the British actress Ellen Tree. The letters from John Lord, Folger MS Y.c.2599 (265-268), 1844-1846, describe his first impressions of England, Ireland and the Continent, politics, religion, and Anglo-American relations. There are also a few miscellaneous papers, Folger MS Y.c.2599 (311-323), including Delia Bacon's "Author's Apology and Claim" [1857?]; prospectus' for two of her Historical Lessons, November [1852] (her lecture series in New York) and February 1853 (her lecture series in Brooklyn); three newspaper cuttings; an engraving of Leonard Bacon, a memorandum concerning the publication of The Bride of Fort Edward, and an inventory of items from the school run by Delia, Julia, and Alice Bacon in Jamaica, Long Island, sold in 1830 for $130.59 in order to repay their creditors.

List of correspondents: Mrs. Alice Bacon; Benjamin W. Bacon; David Bacon; George Blagden Bacon; Leonard Bacon; Leonard W. Bacon; Lucy J. Bacon; Theodore Bacon; George Bancroft; Sarah C. Becker; Catherine E. Beecher; Francis Bennoch; James Buchanan; Charles Butler; Jane and Thomas Carlyle; Messrs. Chapman and Hall; Rufus Choate; Samuel Colman; J.P. Collier; Messrs. Dix and Edwards; Sir Henry Ellis; R.W. Emerson; Edward Everett; Eliza R. Farrar; George Fayrer; C.C. Felton; Celina Flower; G.J. Granville; Mrs. W. Grote; Francis L. Hawks; Nathaniel and Sophia Hawthorne; Arthur Helps; Herriman and Brink; George S. Hillard; Marcus Hodges; R.M. Milnes (later Lord Houghton); J.B. Hume; M. Jones; Rose H. Lathrop; J? T? Lipscomb; George Littlewood; Sampson Low, Son, & Co.; John Lord; E.B. Lytton (later Baron Lytton); James Martineau; Maria Mitchell; John Murray; Anthony Panizzi; J.W. Parker; Elizabeth Peabody; George Peabody; Alice Bacon Peck; Phillips, Sampson & Co.; George Palmer Putnam; Bernard and David Rice; Mr. and Mrs. George Ripley; Sarah S. Robbins; Benjamin Silliman; Augustus R. Sleet; Harriet B. Stowe; Thomas H. Taylor, the editor of the Tribune; Jonathan M. Wainwright; Thomas S. Williams; and Julia Bacon Woodruff.