Convened by Pope John XXIII, the Second Vatican Council (1962-65) profoundly changed the self-image and life of the Catholic Church. But understanding, interpreting, and implementing Vatican II still remain a task far from completed. Pope Francis has given fresh impetus toward practicing the Council's teaching about a humble, servant Church that pursues justice and peace for the whole world. This book explores and presents Vatican II's developments in doctrine about divine revelation; the nature, mission, and collegiality of the Church; religious freedom; and the divine grace that reaches all human beings. It takes up the profound significance of the liturgy constitution, which opened the way for the Council's subsequent teaching. In documenting the renewal and reform conveyed by the message and meaning of Vatican II, this book illustrates the scholarship and accessible style for which Gerald O'Collins has become renowned.