The defining features of chamber music are explored over the course of nine chapters. From sixteenth-century Europe through to the present-day global marketplace, the space of the “chamber” has defined the genre and determined the size of ensembles. Developments in music publishing, from the formatting of scores to the cost of buying them, have also influenced participation in playing chamber music. Private social circles have been replicated in the organization of public concert life, and chamber-music societies have increasingly presented specialized programs that have reinforced a historical canon. Chamber music and its musicians have repeatedly reflected and been impacted by political and social change, as well as by media technologies.