The Rare Books Collection contains more than 30,000 volumes, with strengths in theology, philosophy, Church history, English recusant history, and works written by or about members of the Society of Jesus. Items of note include 12 incunabula (books printed before 1501), including a leaf of the Gutenberg Bible; many works by the seventeenth-century Jesuit polymath Athanasius Kircher; works by Petrus Ramus, including a volume of Arithmetices that has annotations thought to be Ramus' own hand; and the 1662 Atlas major of Joan Blaeu in eleven hand-colored volumes. The collection also features a diverse range of medical texts. Key works include a 1568 edition of Vesalius’ De humani corporis fabrica, William Cowper’s influential and controversial Anatomy of the Humane Bodies, along with his student, William Cheselden's, similarly named anatomical guide, The Anatomy of the Human Body.