The Edwin Tappan Adney papers contain materials created or collected by Adney relating to First Nations' linguistics, ethnology, heraldry, and other related topics of interest. The majority of the material is typewritten notes. All of the material has been left in the original order within the folders, labeled with the original title or label if one was provided. The spellings of names in this finding aid reflect Adney's spellings; they are not reflective of the current spellings of names, for example, Adney referred to the Maliseet people as "Malecite". It should also be noted that the names and titles of Adney's work do not reflect modern cultural sensitivities or politically correct naming conventions, instead they reflect the time in which Adney and his contemporaries worked. Any name or reference that was changed for sensitivity reasons, will be found in brackets. As mentioned in the above biographical note, this material comprises only a select part of Adney's manuscript material, his archival materials were divided among different repositories after his death per his expressed wishes. This collection contains five series.

Series I. Linguistics contains Adney's notes and manuscripts about his study of First Nations' languages. The language and vocabulary material is about the Maliseet language, unless otherwise noted; other languages include Micmac, Beothuk, and Algonkian. The material in the folders labeled "Notes" have been left in the original order in which they were found. Some of it may be parts of a manuscript or research for a different topic. Some of the linguistic data about names and places contains correspondence and news clippings, in addition to the notes. This series has been divided into two subseries. Subseries A. Language and Grammar contains notes, manuscripts, and research material about the rules of the various languages that Adney studied. Most of this material was originally in boxes labeled "Miscellaneous language and grammar", with little to no information to further identify it. For this reason, the materials have been left in the order in which they were found, and identified when possible. Subseries B. Vocabulary contains notes, research, and some of Adney's manuscripts on the First Nations' vocabulary.

Series II. Individual Tribes contains research and notes about individual tribes. This material has been organized by the name of the particular tribe: Beothuk, Blackfeet, Eskimo, Iroquois, Maliseet, Passamaquoddy, and Western tribes. The Maliseet material is the most prolific.

Series III. Other Research/Topics of Interest contains material about other research areas that Adney had an interest in. This material includes notes, manuscripts, sketches, photographs, news clippings, and has been divided into seven subseries. Subseries A. Canoes contains materials relating to Adney's study of birch bark canoes, including research notes, sketches, and photographs. Subseries B. Heraldic Art contains research notes, sketches, and drawings of heraldry and crests. Subseries C. Treaties/Political Status of First Nations contains material relating to various treaties involving First Nations, and the political status and rights of the people of the various tribes. Adney was an advocate for the fair treatment of the First Nations, and lobbied on their behalf at numerous times. Subseries D. Mythology, Astronomy, and Natural History contains material researched and collected by Adney about First Nations' mythology, astronomy, and natural history. This subseries contains notes, research material, drawings, and photographs. Of interest is a sample that Adney collected of a fern, known as a Fiddlehead (box 30, folder 1). Subseries E. Ethnology contains research, notes and sketches about the characteristics of the various tribes that Adney studied. Of particular interest in this subseries is a volume of sketches of "picture writing" found at Lake Missinaibi, Ontario.

Subseries F. Norse Correlations contains materials relating to the idea of correlations between the First Nations and Norsemen, and the Norsemen's travels to North America. Subseries G. Animals and Trapping contains materials relating to Adney's study of animals and their relationship to the First Nations. This subseries also contains material about the trapping of animals and the fur trade. Subseries H. Tobacco contains research notes, photographs, and samples of tobacco. Subseries I. Notebooks and Miscellaneous Research contains Adney's notebooks, research notes on miscellaneous topics including other people's publications with Adney's notes, and news clippings on various topics. Included in this subseries are some news articles written by Adney.

Series IV. Correspondence contains correspondence sent or received by Adney, and mostly relate to his work and studies. Personal correspondence has been filed in separate folders, but has been organized by items sent or received by Adney. All materials have been organized by year. This series has been divided into three subseries. Subseries A. From Adney contains correspondence written by Adney. Subseries B. To Adney contains correspondence written to Adney. Subseries C. Other contains correspondence that was neither written by or to Adney, but was kept with his collection. There is one letter written to a Doctor Waterhouse, dated March 5, 1821, which discusses Cherokee and Osage Native Americans; it is possible that Adney collected this letter for his research.

Series V. Other contains miscellaneous items found in the collection. Included in this series are brochures and programs for events that Adney likely attended, some pages from a personal diary or journal, some financial papers, a deed of gift, list of ethnological models, and Adney family genealogy. The items in this series have been organized by date.