The William Innes Homer Papers includes materials relating to William Innes Homer's (1929-2012) research, publication and teaching materials dating from as early as the 1890s to 2004, with the bulk of the material from the late 1960s through the 1970s. Materials include: correspondence with artists and their relatives, published articles and papers, photocopies or photographic prints of rare ephemera and catalogues related to the early American modernist movement, theses, dissertations, many lectures presented by Homer, handwritten research notes, and photocopies of texts, some of which are annotated. The collection documents Homer's extensive research and scholarly explorations on modernist painting, photography, and modern and postmodern criticism that demonstrate his role as a teacher and investigator of these subjects. There are published and unpublished materials, and format varies: paper, microfilm, photographs, audiocassette tapes, and film. There are extensive photocopies of books and articles, as well as materials from other research libraries, such as the Beinecke Rare Book and Manuscript Library, Yale University, and the Archives of American Art. Also included are audiocassette recordings of interviews Homer conducted with artists or relatives and friends of artists, some of which include transcripts, transcriptions of Homer's research into artists' archives, and Homer's collection of other scholars' bibliographies as well as those he created.

The main subjects of the collection include: early American modernism, the Photo-Secession, pictorial photography, Alfred Stieglitz, the Stieglitz Circle of artists (Arthur Dove, Georgia O'Keeffe, Marsden Hartley, and John Marin), modernism and postmodernism, Critical Theory, and contemporary society. The bulk of the collection pertains to American modernists in the fields of painting, illustration, and photography, and documents the work of numerous well-known (as well as many underrepresented) artists from the late-nineteenth through the twentieth centuries, and especially that of women painters and photographers. The collection also includes research for Homer's book, The Language of Contemporary Criticism Clarified. In its attention to a wide range of topics and materials, the collection explores major art developments, theories about modernism and Postmodernism, and technologies.