These records pre-date the official founding of the Society in 1787. Included is a letter from Archbishop Becker to Reverend Dr. Johnson, October 1768, concerning the founding of a missionary society in Boston; an inquiry letter from Dr. Hale into the Society's history, May 1898; a newspaper article on the origins of the Society's history as discussed at the annual meeting, 2 June 1899; a series of letters from missionary Gideon Hawley to Edward Wigglesworth from various spots in Maine and Massachusetts spreading the gospel among the Native Americans, 1752-1756; and "The Commission by The Society in Scotland for Propagating Christian Knowledge to the Gentlemen within named as a corresponding Board at Boston, North America, March 1787."

These diaries were kept by missionaries in the field as documentation of their daily work. Included are five diaries of Reverend Samuel Kirkland, a missionary sponsored by the Society in Scotland and Corporation of Harvard College to the Oneida Nation and others of the Six Nations, June 1787-October 1791; two journals of John Sergeant with the Oneida in Massachusetts, 1791; an extract from a journal of John Strickland in Hancock and Washington counties, Maine, 1796; William Maclean's journal during his time in Camden, Maine, and the surrounding areas, 1800; two journals of John Sawyer in Brewer and Bangor, Maine, 1828-1832; and one long report of Reverend George F. Kenngott from his travels out west, July-August 1910. The latter's report includes typewritten documentation of his visits to missions, as well as photographs of the missions and their inhabitants.

This subseries primarily consists of letters from missionaries to Society members describing their work up to 1838, living and traveling among the Native Americans in New England and New York. The bulk of this period, until the middle of the century, consists of correspondence to Abiel Holmes, secretary of the Society, and head of the Select Committee. Holmes was a noted Congregationalist and the father of the poet Oliver Wendell Holmes. Notable among the other correspondents are Elijah Kellogg, working among the Passamaquoddy tribe in Perry Point, Maine, and Frederick Baylies, missionary to the Narragansetts in Edgartown, Massachusetts.

There is some overlap of subject and style between these personal letters and the missionary diaries from the 1787-1832 period, as well as some brief diaries included in the general correspondence. Included is documentation of daily activities, i.e. preaching and baptisms, as well as descriptions of lifestyle and health problems, but very little reflecting the Native American point of view. More of that aspect may be located in the journals or diaries.

Around the mid-1840s, the correspondence becomes more business-oriented and less personal. The missionary correspondence is more sparse and focuses more on requests for payment of salary and the need of resources for the missions, rather than descriptions of the missionaries' lives among the Native Americans. Correspondence from Abraham Plumer, missionary at Damariscotta and other parts of Maine, provides good insight into the thoughts of a Society missionary.

The correspondence from 1851-1857 is very sparse, and there are only two letters representing the 1858-1862 period, with another gap from 1862-1874. The bulk of the letters from this early middle period is between Society officers concerning business matters. Noteworthy among the officers of this period are treasurer James Savage and secretary Francis Parkman. Letters between these two concern payment of missionaries and recommendations of new missionaries.

The 1874-1922 period is characterized by correspondence from industrial school officers describing in depth the work of their institutions and requesting financial assistance from the Society. These institutions vary from schools for Black students in the south, such as Claflin University and Calhoun Colored School in Alabama, to Scandinavian missions in the north and midwest. Some are schools for Native Americans like White River Indian Agency in Colorado and Twinsburg Seminary for Indian Youth in Ohio. The main recipients of this correspondence are secretary Rufus Ellis and treasurer Thornton K. Lothrop.

At this time, the Society still sponsored individual missions in New England, among them the Isle of Shoals mission, the Gay Head mission, and Samuel May's mission for the Onondaga Nation. These reports are similar to the earlier correspondence. In particular, the letters of Mrs. L. M. Wight from her mission in Versailles, New York, give good insight into Native American mission life. Other correspondence of interest includes nine letters from Native American students of Siletz Indian Agency in Oregon to their missionary Thomas Eliot in March 1882. During the 1880s and 1890s, there are also letters between missionaries and government officials concerning reservations and assimilation policies.

All missionaries and organizations receiving appropriations from the Society wrote detailed annual reports of expenditures and progress. Significant among these correspondents is Booker T. Washington, president of Tuskegee Normal School. His many letters contain lengthy descriptions of this type of agricultural university for Black students in the 1890s and early 20th century.

Correspondence after 1922 is more business-oriented and doesn't describe missionary or student life, so it has been filed with the business section.

This series contains general business records central to the organization and running of the Society, other than the financial records. These include the 1924 by-laws; annual meeting minutes and announcements; certificates and appointments of missionaries and officers; lists of officers; and miscellaneous reports.

Also included are reports of the Select Committee, loose and bound annual reports, and minutes written by the secretary to document expenditures and progress in propagating the gospel. The secretary lists the organizations and missionaries receiving appropriations and describes the reports he has received from them. These school reports often discuss specific pupils and what they are learning.

Included is a treasurer's list of yearly expenses and income.

Included is a blueprint of plans for a mission school in 1880 and miscellaneous deeds, 1849, 1857.

This subseries contains materials by or about the Society for Propagating the Gospel Among the Indians and Others in North America, hereafter abbreviated as SPGAIONA.