The book for our class are reflections on a hymn, Veni Creator, in Latin, or in English it is Come, Creator Spirit. The hymn was composed by Rhabanus Maurus (780-856), who was priest and Archbishop of Mainz. Cantalamessa notes that Luther and Teerstegen (a mystic who was the source of many of John Wesley's hymns) used the hymn. While I am unfamiliar with the text, I am happy to have had this glad awakening.
Cantalamessa writes that the book is not about the hymn, it employs the hymn to reflect on the Holy Spirit. This is what he has done. I'd recommend the book to anyone desiring to reflect on the nature of God and the person of the Holy Spirit. You'll find the text steeped with per-schismatic reflections of the church, especially Pre-Nicean writings, and sprinkled with concerns taking place today.
Here is the Hymn that sets about the ruminations of Cantalamessa.
Come, Creator Spirit,
visit the minds of those who are yours;
fill with heavenly grace
the hearts that you have made
You who are name the Paraclete,
gift of God most high,
living fountain, fire, love
and anointing for the soul.
You are the sevenfold in your gifts,
you are finger of God's right hand,
you, the Father's solemn promise
putting words upon our lips.
Kindle a light in our senses,
pour love into our hearts,
infirmities of this body of ours
overcoming with strength secure.
The enemy drive from us away,
peace then give without delay;
with you as guide to lead the way
we avoid all cause of harm.
Grant we may know the Father through you,
and come to know the Son as well,
and may we always cling in faith
to you, the Spirit of them both.
As well as including this hymn, Cantalamessa includes other prayers/hymns to the Spirit near the end of each chapter. The work is a treasure trove which rightly guides us in worshipping God - Father, Son and Holy Spirit.