Contains manuscripts, notes, and typescripts, compiled by Gates between 1898 and 1940, of source materials in the Chortí language.

Contains photocopies, notes, and typescripts, compiled by Gates between 1898 and 1940, of source materials in the Huastec language.

Contains numerous photocopies, manuscripts, notes, and typescripts, compiled by Gates between 1898 and 1940, of source materials in the Maya language.

Contains photocopies, typescripts, manuscripts, and notes of texts collected by Gates in various Mesoamerican languages.

Contains hand-written, typed, and photographic notes on various Mesoamerican codices and glyphs in addition to an extensive card file for glyph identification. The notes were compiled by Gates both in the field and in California and Baltimore between the years 1898 and 1940.

Contains writings related to Gates' institutional affiliations with the Aryan Theosophical Society, the San Diego Museum, and the Department of Middle American Research at Tulane University. While his work with the Department of Middle American Research at Tulane University was directly related to the study of Mesoamerica, Gates' affiliations with the Aryan Theosophical Society and the San Diego Museum were not related to the study of Mesoamerica.

Contains notes on Mesoamerican astrology and calindrics compiled by Gates between the years 1898 and 1940.

Contains notes, compiled by Gates between 1898 and 1940, on the grammars and vocabularies of various Mesoamerican languages including Tzeltal, Quiché, Maya, and Motul.

Contains Gates' research notes, produced both in the field (Southern Mexico and Guatemala) and in Baltimore and California, between the years 1898 and 1940, on various codices, early Mesoamerican vocabularies and grammatical studies, as well as astrological and calindrical studies. Many of the notes are in organized into lengthy charts and tables.

Contains selected writings of Gates prior to 1930, including notes, printed studies and articles, and public addresses. All items pertain to the study of Mesoamerica, with the exception of an article on the conditions in post-revolution Mexico and an article on Chinese art.