Collection consists of materials relating to the published and unpublished works of bookseller, book collector, and bibliographer Percy Muir, together with a small quantity of papers relating to the antiquarian bookselling firm Elkin Mathews, Ltd. The bulk of this collection is comprised of Muir's loose-leaf notes on British imprints. Muir aspired to produce a dictionary of imprints that would trace the links between printing or publishing businesses over time. This project began ca. 1931, inspired by a client's query, and was apparently never completed to Muir's satisfaction. He discusses some preliminary findings in the 1933 essay "English Imprints After 1640", published in The Library, but the dictionary represented in this collection remains unpublished. Each "entry" in the imprints notes contains the following information: imprint (printing or publishing business) at head of page, followed by a list of publication dates, and the address at which the business was found at each date. These listings are corroborated with reference to various bibliographies and dictionaries of publishers. The collection contains the manuscript (178 handwritten pages) of an untitled and unpublished novel, the tale of a young man's entry into the book trade. The novel appears to be semi-autobiographical, although it is written in the third person. The imprints notes and novel manuscript are written on the verso of various earlier notes, manuscripts, typescripts, printed proofs, and calling cards. Of particular interest, and scattered throughout, are: Muir's 1954 work, English children's books: 1600-1900 (the chapter entitled "A monstrous regiment" is particularly well-represented), in various stages from manuscript to printed pages; Muir's notes on European music publishers, in a format similar to the British Imprints notes; and various anecdotes in Muir's hand. A lengthy fragment, in pencil, of a translation of Friedrich Chrysander's G.F. Händel can be found on the verso of p. 165-178 of the novel manuscript. Also included in the collection are several invoices from the Elkin Mathews business, and a suggested "arrangement of sold-cards."