- Manuscript copy in Lysander Spooner's hand of a four-page letter dated April 12, 1845, from Thomas Earle in Philadelphia [Pennsylvania] to G. [George] Bradburn, in which he gives a lengthy critique of Lysander Spooner's book [probably The Unconstitutionality of Slavery] and the abolitionist movement in general., New-York Historical Society
- Four-page letter dated September 8, 1845, from Geo. [George] Bradburn in Bangor [Maine] to Lysander Spooner of Boston, Massachusetts, describing several newspaper and circular reviews of Spooner's book [The Unconstitutionality of Slavery], mentioning opinions given by [William Lloyd] Garrison and Bob [Robert?] Phillips., New-York Historical Society
- Draft of two-page letter dated September 19, 1845, from L.S. [Lysander Spooner] of Boston [Massachusetts] to [George] Bradburn notifying him of the sale of the Boston Chronicle to Hiram Cummings, and encouraging him to "start a paper" in Boston with the backing of Richard Hildreth., New-York Historical Society
- Four-page letter dated August 25, 1847, from L. [Lysander] Spooner in Boston [Massachusetts] to George Bradburn in Cleveland, Ohio, instructing on where to send letters to Mrs. [Elizabeth] Sargeant, and to pick up a letter from her friend, Miss Julia Johnson. Also discusses abolitionist activities and arguments appearing in Spooner's new book., New-York Historical Society
- One-page letter dated July 18, 1848, from L. [Lysander] Spooner in Boston [Massachusetts] to [George] Bradburn, notifying that he is leaving Boston for Athol because he has "nothing to eat" and that "the Abolitionists must flounder in their ignorance until they are willing to give me bread in exchange for knowledge.", New-York Historical Society
- One-page letter dated December 28, 1850, from Stephen P. Andrews in New York City, to Lysander Spooner of Boston [Massachusetts], reporting on the distribution of books sent by Spooner to Freeman Hunt, [William Cullen] Bryant, [Horace] Greeley, and Park [Parke] Godwin. Includes mention of a "card" [possibly a petition] that Andrews suggests having signed in Boston and then sent to New York for additional singatures., New-York Historical Society