The Counter-Reformation Collection includes over 3500 volumes of primary source materials showing the Catholic response to the Protestant Reformation up to the time of the French Revolution. It embraces apologetic works by Catholic theologians such as Johannes Cochlaeus, Johann Eck, and Nicholas Sanders. Many of these works are in Latin; there are also items in German, Italian, French, Spanish, and English. The collection also includes treatises on prayer and the spiritual life, catechetical works, manuals for confession, sermons, and lives of the saints.
The collection was organised in 1969, building upon materials already present in the Library; since that time it has benefitted from several major grants. The collection is complemented by the Library's significant number of general theological works and works about English recusancy.