From the University of Iowa School of Library and Information Science's website:

"Book studies is an interdisciplinary field that considers the role of books in cultural and material history. Individuals interested in this field of study may consider becoming rare books librarians. There is overlap between the areas of special collections and rare books librarianships, but rare books librarians typically work with published materials, both hand-pressed and machine pressed, while special collections librarians may work with a wider selection of materials. Rare books librarians develop specialized subject knowledge in book materials, construction, and preservation needs."