Microfilm is material on film that require a viewer in order to use. The microfilm collection covers a broad range of subjects. The microfilm collection is very useful because it contains materials that aren't printed anymore, not digitized, or we do not have a subscription to.
Various microfilm such as Government Documents and music scores are located in the general collection. All of these are organized by Library of Congress (LC/LoC) Classification System. You can find the categorical breakdown here. However, there are also Government documents located on the first floor and organized by SuDoc, or Superintendent of Documents Classification System.
The periodical collections are located separately nearby. These include newspapers, journals, cinema press books, and more. These are located further along the microform collection area. The periodicals are organized by title.