The Peter F. Neumeyer Papers document Neumeyer's professional and academic career, beginning as a student and ending as a critic. The papers date from 1950, when Neumeyer was an undergraduate, to 2004, when he and wife Helen co-curated an exhibition on illustrator Margot Zemach. The bulk of the papers are from the 1970s through the 1990s when Neumeyer was a professor and actively published academic articles, reviews, and poetry. A recent addition to the papers, includes the outgoing correspondence from Peter Neumeyer to Edward "Ted" Gorey, 1968-1971. The collection is divided into five series: Pedagogical Work, Professional Files, Published Work, Margot Zemach Art Show and Correspondence with Edward "Ted" Gorey. Neumeyer kept all of his papers in a series of labeled folders. This order was preserved, and the folders that comprise each of the five series are arranged alphabetically based upon, in most cases, Neumeyer’s description or by chronological order.

The Pedagogical Work series dates from 1947-1992. The series documents Neumeyer's career as both student and educator, as well as his role in developing the Children's Literature Program at SDSU. It begins with coursework from Neumeyer's undergraduate and graduate classes. The bulk of the series, however, consists of lecture notes, children’s literature course readers, quizzes and assignments, and class handouts. These materials date back to Neumeyer’s time at Harvard, but are predominantly from courses he taught at San Diego State. One of the most significant documents in this series is a semester project from Neumeyer’s seminar in Children’s Literature at Harvard in 1966. This project was an early attempt to approach children’s books from a literary—in this case structuralist—approach. This series offers an invaluable look at the progression of children’s literature as an academic subject as taught by one of its prominent scholars. The series is filed alphabetically by file name.

The Professional Files series dates from at least 1978, though there are many undated folders that probably predate that year, and go up to 2004. This series documents Neumeyer's professional and academic interests outside of teaching. The Professional Files consist of folders that Neumeyer kept on various subjects related to children's literature and literature in general. These files pertain to Neumeyer's research interests and academic writing as opposed to his teaching. It also contains correspondence, especially regarding The Annotated Charlotte's Web and the introduction to the 50th Anniversary Edition of Charlotte's Web that Neumeyer wrote. Other materials include illustrations and proofs by Richard Burhans, collaborator with Neumeyer on an adaptation of The Phantom of the Opera. Other subjects range from authors like Lewis Carroll and Richard Kennedy to poet John Clare, to children's literature bibliographies and history. The series is filed alphabetically by file name.

The Published Work series dates from 1963 to 2001. The series documents Neumeyer's written work, including published articles and poems, as well as manuscripts of articles, reviews, and unpublished texts. There are academic articles published in scholarly journals, poetry published in literary journals, children's books reviews, translations of children's books from German, manuscripts of unpublished books, and a language arts and reading program entitled Interaction, co-authored by Helen and Peter Neumeyer along with others. There are drafts of his introduction for the 50th Anniversary Edition of Charlotte's Web, as well as many other articles about E.B. White and his career. As noted above, Neumeyer wrote book reviews for a wide array of publications. The series is filed alphabetically by file name.

The Margot Zemach Art Show series dates from 2003-2004. The series documents Peter and Helen Neumeyer's involvement in the preparation and operation of this exhibit. Zemach was an artist and illustrator of children's books. The show, curated by the Neumeyers, was held at the Eric Carle Museum of Picture Book Art in Amherst, MA. The series contains biographical information on Zemach, correspondence with the museum director, contracts, logistical and planning information, and other related materials. The series is filed alphabetically by file name.

The Correspondence with Edward "Ted" Gorey series dates from 1968-1971. It was during this time, Neumeyer was introduced to the idea of collaborating with Gorey and the letters reflect literary discussions and the exchange of ideas about the published work Donald Has a Difficulty and subsequently, Donald and the... Soon after, Neumeyer addressed Edward Gorey as "Ted". The letters are typed, handwritten, and carbon copies of Neumeyer's outgoing letters, typescripts of Neumeyer's initial story of Donald Has a Difficulty, handwritten or typed notes, and various newspaper clippings and enclosures. The letters also include a poem titled "The Last Stoejgnpf or, Donald Takes a Pet" that Gorey edited with handwritten annotations. The collection of letters both from Neumeyer and received from Gorey are the basis for the book, Floating Worlds: The Letters of Edward Gorey and Peter F. Neumeyer.