Center for Popular MusicThe Center for Popular Music makes available a wide variety of music and related materials for research and study, all available and searchable online. From original 18th-century tune books to digital files, the CPM's special collections contain all popular formats of music dissemination. Collections of music include sheet music, song broadsides, rare books and scores, and sound recordings. The CPM also collects related materials that further enable the study of popular music, such as photographs, trade catalogs, posters, playbills, and programs, periodicals, vertical files, and manuscripts.