This study of Roman Catholic ecumenism, concentrating on the period 1942 to 1960, draws on original sources from both Germany and the Vatican. It provides convincing evidence for its claim that Cardinal Augustin Bea opened up for the Catholic world the theological field of ecumenism. He accomplished this through the disclosure of the doctrinal and biblical foundations of the ecumenical endeavour itself. He also addressed ecumenism's future by pointing out the necessity of Christian contact and conversation. Bilateral and multilateral exchanges eventually would provide the road map for reconciliation and Christian unity. As such, that quest is based upon that particular unity inherent in the Sacrament of Baptism (pp. 271f).

It was the approach of Cardinal Bea and his colleague, Archbishop Lorenz Jaeger of Paderborn, to Pope John xxiii, in a letter of 4 March 1960, which led to the formation of the Secretariat for Promoting Christian Unity, of which Bea was made first president. When asked why Bea was so quickly chosen for the office, Archbishop Louis Capovilla, Pope John's private secretary, replied ‘Because he was a German!’ His German experience meant that Bea had worked in a deeply divided Germany, broken into east and west states after the Second World War. Hence he was convinced of the urgency of Christian unity, not only for the Church, but for humankind as a whole. He knew experientially that a divided Church could not with integrity or effectiveness preach unity to a divided world. Vereb traces the significant factors in the development of twentieth-century Catholic ecumenism: the 1948 Assembly of the World Council of Churches, attended by Roman Catholic observers; the formation of CCEQ (Catholic Conference for Ecumenical Questions, 1949), which brought together Catholic theologians and those of other Churches; and Pope John's calling of the Second Vatican Council (1962–5), with the ultimate aim of Christian union. Bea was an eminent theologian, whose distinctive emphasis on the central importance of Christian baptism was to prove of vital importance for ecumenism. He stressed that baptism, as incorporation into ‘Christ the Royal priest’, brought with it responsibility for both the Church and the world. The author writes partly to express his gratitude for the ecumenical education he received as a staff member of the Secretariat for Promoting Christian Unity, but also because he judges that ecumenical enthusiasm is tending to wane around the world. If that is so, this study should certainly help to rekindle it among both Roman Catholics and their sister Churches.