This book introduces the study of the doctrine of the church. David Emerton highlights the breadth of contemporary ecclesiological thought by articulating five approaches to ecclesiology. He argues that we must ask what the church is before asking what the church does. Professors will find a valuable orienting text, students will grasp the stakes of contemporary debates, and scholars surveying ecumenical ecclesiology will discover an illuminating structural framework. Doing the work of the church requires discerning its essence, and this timely volume insightfully examines what is at the heart of the body of Christ.