The mixed results of the ecumenical dialogue since the Second Vatican Council have made it clear that the primacy of the Bishop of Rome remains the single most serious obstacle on the path of ecumenism.

In his landmark 1995 encyclical Ut unum sint, Pope John Paul II reiterated the constant teaching that the Catholic Church "has preserved the ministry of the Successor of the Apostle Peter, the Bishop of Rome". He also invited leaders and theologians of other Christian communities to engage in a "patient and fraternal dialogue on this subject…to find a way of exercising the primacy which, while in no way renouncing what is essential to its mission, is nonetheless open to a new situation".

This book explores in depth the discussion of papal primacy in the Catholic-Orthodox, Catholic-Lutheran and Catholic Anglican dialogues, along with an appendix on the concept of "Sister Churches". Each chapter describes how the primacy is viewed in the respective churches or ecclesial communities, then it analyzes the documents of the official ecumenical dialogue and realistically evaluates the results achieved thus far.