In October 1958, Pope Pius XII urged a party of pilgrims to lift up their minds, as he was doing in those last days of his life, to God's holy angels. "They are so glorious," he said, "so pure, so wonderful, yet are given to be your companions, charged to watch carefully over you, lest you fall away from Christ, their Lord." In this book, Fr. John Saward urges us to take up the great pope's invitation to discover the World Invisible of the holy angels, with whom we hope to enjoy the eternal happiness of heaven. Here is a work born of long years of study and teaching, and of contemplation, under the tutelage of St. Thomas Aquinas, the Angelic Doctor. To help us understand better the truth of the angels, Fr. Saward points the reader to the beauty of the angels as glimpsed in the Divine Comedy of Dante and the drawings of Botticelli. After long years of neglect by theology professors of the English-speaking world, World Invisible restores to the angels, holy and fallen, their proper place within the sacred doctrine of the Catholic Church.