The title 'Advent' refers, not to the season, but to the general work of preparing men for Christ, and the book deals with what is involved in conversion to Christianity. Pere Danielou begins by posing the since we say it is possible for those outside the Church to be saved, why do we insist that everyone ought to be a Catholic? Do we look upon other religions in the optimistic light that much of what they contain is true and therefore a preparation for Christ; or in the pessimistic light that they contain much that is false and by the hold they have on men are the greatest barrier to the coming of the age of the fullness of Christ? The book answers the question by showing how the great precursors have behaved throughout how Melchisedech, representing natural religion, stood back to welcome revealed religion; how Abraham gave up the paganism he understood to follow God in the darkness of faith; how John the Baptist led the Jews to Christ and then faded out himself; how Our Lady gave up many of her natural rights as a mother to become the mother of Christ's Mystical Body — these are the major examples, but there are others as well. Although Christ came not to destroy but to fulfill, yet there was much he destroyed or at least rendered empty and meaning- less; and this book shows in a grand sweep of history how' God's plan has always followed this pattern and continues to do so in individual sanctification as well as in the conversion of nations. The answer, says the author, lies in the Cross. All the perfectly good human hopes Christ had raised were shattered and only through the Cross came triumph and true hope.