One and a half document boxes highlight I. R. Brussel's career as a book scout. Containing mainly correspondence, the collection also includes clippings, illustrations, invoices, printed materials, and a very few photographs. The collection is arranged into three series: I. Individual Correspondence, 1925-1969 (bulk 1929-1935); II. General Correspondence, 1930-1972 (bulk 1950-1970); and III. Other Materials, 1903-1973. Although the date range of the collection spans seventy years, only a single printed item dates from earlier than 1929.

The I.R. Brussel papers consist mainly of incoming correspondence from the many authors, book dealers, and book collectors who were both colleagues and friends of Brussel, with very few responses by Brussel present. Taken as a whole, the collection highlights Brussel's work in the book trade over five decades. The papers illustrate Brussel's varied activities within the literary community, from his attempts to bring together authors and illustrators such as James Branch Cabell and Frank C. Papé for literary ventures, to his work tracking down rare and unique items on behalf of collectors and scholars. Particularly well illustrated in this collection is Brussel's connection with the book scene in London, although he was based in Brooklyn. A small amount of printed materials relating to the book trade is also found in this collection. Little, if any, documentation pertaining to Brussel's personal life is present.

Series I and II contain correspondence from book designers, collectors, writers, bookstores, bibliographers, libraries, and other dealers. The correspondents in Series I had relatively long-term connections with Brussel; their letters are arranged alphabetically by name, and chronologically within each folder. Found in this series are letters from author James Branch Cabell and his wife, novelist Dorothy Richardson, illustrators Frank C. Papé and Alan Odle, collectors William White and Clark Wikle, and literary contacts Francis and Grace Norman. Most of the correspondence in this series tends to be rather perfunctory and business-like; for example, the correspondence from Dorothy Richardson generally pertains to the dispersal of her manuscript and book collection, with some references to literary rights and new editions of her work. The Normans, however, wrote chatty letters, describing their recent activities and those of mutual acquaintances. Most of the letters in this series date from the early 1930s. The correspondence in Series II consists mainly of single or short exchanges with Brussel, and these letters have been arranged alphabetically within two folders. Most of these letters date from the 1950s to 1970, and pertain largely to business matters, with an emphasis on Brussel's ability to track down rare materials. Correspondence with a few authors of some renown, such as A. E. Housman, Sir Hugh Walpole, and Sylvia Townsend Warner, is present in this series, but their letters tend to be very short replies to requests from Brussel.

Series III, Other Materials, contains printed materials, notes, clippings, reprints, and cards relating to books, the book trade community, and travel. Of note in this series is a photocopied typed note on Brussel's letterhead relating the disappearance of a manuscript by his father. It seems to reflect his speaking style, and is one of the only items in the collection to offer insight into Brussel's personality. Two pen and ink illustrations by Frank C. Papé, one a bookplate design, are also part of Series III.