This book offers an introduction to the theological and historical aspects of the papacy, an office and institution that is unique in this world. Gerhard Cardinal Mèuller draws on his experience of working closely with the pope every day as Prefect of the Congregation for the Doctrine of the Faith. He addresses, in particular, those dimensions of the papal office which are crucial for understanding more deeply the pope as a visible principle of the church's unity. The book offers insights into the ecumenical controversies about the papacy throughout the centuries, in their historical context"--