Verbum Domini, actually. It's a play on the previous big paper from Vatican II, Dei Verbum.

Aeh, Latin declensions and the way it makes it possible to play with word order. So useful, so beautiful, so confusing without rote memorization. Sigh. Makes me paranoid.

There's some good though brief thoughts about liturgical music in the liturgy/Word section of this thing. (It's a mini-book on the relationship between Scripture and the Church, and God and the Word. Seriously. 208 page PDF,and even without the footnotes it'd be huge. Very readable, though.) He does explicitly cite "the importance of Gregorian chant", of course. :)

"As part of the enhancement of the word of God in the liturgy, attention should also be paid to the use of song at the times called for by the particular rite. Preference should be given to songs which are of clear biblical inspiration and which express, through the harmony of music and words, the beauty of God's word. We would do well to make the most of those songs handed down to us by the Church’s tradition which respect this criterion. I think in particular of the importance of Gregorian chant."

There's also this bit: "The relationship between the word of God and culture has found expression in many areas, especially in the arts. For this reason, the great tradition of East and West has always esteemed works of art inspired by sacred Scripture, as for example the figurative arts and architecture, literature and music... I encourage the competent offices and groups to promote in the Church a solid formation of artists with regard to sacred Scripture in the light of the Church's living Tradition and her magisterium."

Internet use for the faith is also encouraged, though of course the Holy Father reminds people that it can't replace physical presence that's face to face. "In the world of the internet... the face of Christ needs to be seen and His voice heard, for 'if there is no room for Christ, there is no room for man.'"

More importantly, the whole book uses as a continuing theme the likening of Scripture to a polyphonic hymn, which is sung in many languages all at once, but which all says the same thing. The cosmos itself is a symphony. He quotes himself saying in a homily from last year that "In this symphony one finds, at a certain point, what would be called in musical terms a "solo", a theme entrusted to a single instrument or voice which is so important that the meaning of the entire work depends on it. This "solo" is Jesus... The Son of Man recapitulates in Himself earth and heaven, creation and the Creator, flesh and spirit. He is the center of the cosmos and of history, for in him converge without confusion the author and his work." This sort of thing comes into the text several times.

The Holy Father begins his book with talking about the Word as bringing us complete joy, and he ends his book the same way. "....the proclamation of the word creates communion and brings about joy. This is a profound joy which has its origin in the very heart of the Trinitarian life and which is communicated to us in the Son. This joy is an ineffable gift which the world cannot give. Celebrations can be organized, but not joy." He recommends Mary to us as an example of how proclaiming, listening to, and following the Word of God brings us real everlasting joy. This connects with an earlier little section on Mary, which includes this:

"Here I would like to mention Mary's familiarity with the word of God. This is clearly evident in the Magnificat. There we see in some sense how she identifies with the word, enters into it. In this marvellous canticle of faith, the Virgin sings the praises of the Lord in His own words."

This is a marvelous piece of work. I'm sure it will help Church musicians, since they work with Scripture all the time. It might be nice Advent devotional reading, since it's so long and has plenty of food for thought in even small chunks.