What is church? What makes the church one? While these questions may seem innocuous, church has become conflicted territory, with internal factions, external pressures, and ecumenical turmoil all calling for a more positive, sturdy, more resilient notion of Christian community.Wengert approaches the questions as a Reformation historian. He shows how the New Testament notion of ''marks'' of the church was taken up by Martin Luther and developed by Phillip Melanchthon not as a descriptive tag but as a criterion for authenticity in Christian community. Lathrop, a liturgical theologian, shows concretely how those marks can stamp the worship life of a congregation as well as the evaluative work of congregations with their pastors, bishops, superintendents, and conference ministers.This volume originated as six lectures jointly presented to the Academy of Bishops of the Evangelical Lutheran Church in America in 2001.