The Katherine Arnstein Heinemann Papers consist mainly of autograph and typescript drafts of her poems, as well as manuscript and editorial material relating to her collections Brandings (1988) and Some Inhuman Familiars (1983). A small group of correspondence is also present.

The Arthur C. Hoskins collection contains items directly related to Hoskins and his family, including correspondence and records of expenses, and also items related to Missouri Historical Society activities. Certain items, which are connected to material previously collected by Hoskins, but whose source is unknown, have been placed in the collection because of their convenient connection.

The Herbert Howarth Papers consists of material relating to Howarth's book, Notes on Some Figures Behind T. S. Eliot (1964) and includes his letters to and from T.S. Eliot. Howarth submitted drafts of his text to Eliot for comment and several drafts of the book with marginal corrections by Eliot are housed in the collection. The collection offers a unique opportunity to view the response of the subject of a critical biography to the views of a biographer.

Consists of correspondence from Sylvia Plath and Ted Hughes to Olwyn Hughes, Ted's sister. Also, included is correspondence from Hughes to Graham Ackroyd and Ian Hamilton and typescript and manuscript drafts of Adam and the Sacred Nine.

The Hurst Papers consist of a small quantity of correspondence (most of it between Hurst and her school friend Lois Toensfeldt), the manuscript for her novel Quiet Street, some diary material, and a group of clippings and memorabilia. Special Collections also holds Hurst's personal collection of her published work which includes a complete set of first and variant editions, translations, and other copies of her books.

The William Inge Collection consists of the first edition and production archive for Picnic: A Summer Romance and playbills for various productions of Inge's plays.