Book excerpt: The importance of baptism within Christian history, theology, and practice is of the first order. Rooted in Christian Scripture, baptism is initiation into Jesus Christ and the sacramental beginning of engagement with the church, the body of Christ. In recent decades, the relationship between baptismal theology and ecclesiology has changed. Rather than focusing solely on the implications of baptism for individuals, the center of theological conversation has moved increasingly to the nature of baptism as formative of the church. One of the pioneers in exploring this theological issue in the United States has been the Rev. Dr. Louis Weil, who, from the time he helped author the 1979 Book of Common Prayer, has advocated for an approach called "baptismal ecclesiology." In a number of essays since the 1980s, Dr. Weil has encouraged an increasingly ecumenical conversation around this particular approach to ecclesiology. This ecumenical collection of essays by a distinguished and international group of sixteen scholars continues the conversation on liturgy and ecclesiology begun by Fr. Weil.