This work investigates the essential core of Christian belief and institutional structure that must be preserved amidst the pressures of modern secularization and internal ecclesiastical reform. Hans Küng, a prominent and often controversial Catholic theologian, utilizes his extensive knowledge of historical doctrine and contemporary ecclesiology to argue for a return to the foundational tenets of the faith. He presents a framework that distinguishes between transient historical traditions and the permanent, non-negotiable elements of the Church's mission.

This text is regarded as a significant contribution to post-Vatican II theological discourse, reflecting Küng's characteristic rigor and willingness to challenge established hierarchies. The subject matter points to a dense, scholarly exploration intended for readers familiar with systematic theology and the internal debates of the 20th-century Church.