The word church refers to the visible community in which Christians come together for worship, prayer, communal sharing, instruction, reflection, and mission. Most Christian bodies, but not all, see this visible community as imperfectly representing on earth an invisible communion of saints called together by God in Jesus Christ. The church can thus be viewed as one social institution among many, but also as a shared form of life shaped by profound theological self-understandings. Seen institutionally, the church has subsisted in a variety of communal forms and structures of governance throughout a long and very complex history. Understood theologically, the church has been the object of many varying images, descriptions, terminologies, and conceptualities interwoven with the circumstances of that history. The systematic study of the church in all these interacting dimensions constitutes the field of ecclesiology. This realm of inquiry relates constructively to most of the other principal...