Born from the side of Jesus, pierced on the cross, the church is the living body of Christ. Like Jesus himself, it is both eternal and temporal, spiritual and material, spotless and wounded. Constituted as an integrated, living body, the church is the sacrament of Christ; that is, it reveals Christ to the world and makes him present in the world. It exists in order to evangelize and does this most effectively when its diverse members are united in love. This collection of chapters from scholars from diverse fields offers a fresh approach to Catholic ecclesiology. It is hoped that the reader of this book will discover anew the beauty of the church, a living body always old and ever new.