The roles of the Holy See and papal diplomacy vis-à-vis international organisations have a long and intricate story that spans centuries. Papal Diplomacy and the Quest for Peace explores the encounter between the Holy See and the international order, from the establishment of the United Nations (UN) in 1945 through the pontificate of Pope Paul VI (1963-78). Both Araujo and Lucal have worked for and represented the Holy See in the environment of the UN and, to a lesser extent, other international organisations. Consequently, their investigation is based on not only academic study of papal diplomacy and its relations with international organisations, but also participation in the activities of the Holy See within some of these organisations. They contend that while the Church and international organisations have distinctive goals and interests which can introduce strong differences on particular issues, they nonetheless share other perspectives such as the maintenance of international peace and security.

The Holy See has expressed general approval of the UN, especially its initiatives aimed at ""peaceful coexistence and collaboration between nations."" At the same time the Holy See has not hesitated to state its morally grounded positions on pressing contemporary issues (e.g., family planning, abortion, human embryonic cloning, and family life) that have not always been congruent with those of temporal sovereigns and international organisations, including the UN. To date, Pope Pius XII's initial aspiration to join the UN has not been fulfilled, but the Holy See formalised its participation in the General Assembly of the United Nations in summer of 2004. In spite of occasional criticism by some segments of secular society, the interaction between the Holy See and the UN continues to exist and to be fruitful in a variety of contexts.

Papal Diplomacy and the Quest for Peace seeks to elucidate this encounter and dynamic by examining congruence and divergence on vital issues of great importance to both institutions, most especially the quest for peace and the protection of the dignity and legitimate interests of humanity.