The Bentley does house published materials as well as primary sources. The published materials complement archival materials in terms of subject matter. The library has a wide variety of other types of materials as well, most of which are unique. They include maps, newspapers, audio visual materials, films, radio programs, and photographs. The material held in archives is organized and stored differently than in a library.
Archival material is organized into manuscript collections or record groups.
Examples of record groups are the records of the Ann Arbor Temperance Society, Hannah and Lay Company of Traverse City or the University of Michigan Department of Physics. Manuscript collections and record groups may be as small as a single item or large enough to fill hundreds of boxes. The materials are stored in folders and boxes in a stacks area that is not open to the researcher. The reference staff will show you how to request materials from the stacks. The contents of a collection are not indexed item by item but rather at a folder level.