Cardinal Cassidy devotes part one of his book to Unitatis redintegratio, the decree on Restoring Christian Unity, which brought the Catholic Church into the modern ecumenical movement. And in part two, Nostra aetate (the Declaration on Interreligious Dialogue), he looks at the relationship of the Catholic Church with other world religions.

This work, and indeed the entire series, which is the only one of its kind at this level and organization, will prove valuable for religious educators, theologians, church historians (of all faiths, especially Judaism, Christianity, and Islam), undergrad and grad students, as well as readers who have heard much about Vatican II, but who have never sat down to understand certain aspects of it.