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.