The Rare Book Division consists of two principal units:

General Rare Books: Holdings include approximately 275,000 rare and historically significant printed books in Western languages, with remarkable collections of early European and American imprints, annotated books, historic bindings, emblem books, limited editions, presentation copies, and association copies. The Rare Book Division is especially strong in classical Latin texts; American history and literature; English history and literature; angling and sporting books; and, to a lesser extent, French, German, and Latin American literature. Of special interest are the Morris L. Parrish Collection of Victorian Novelists, the Howard Behrman Collection of American Literature, the Miriam Y. Holden Collection on American Women, the Grenville Kane Collection of Americana, and the Junius Spencer Morgan Collection of Virgil. Recent collecting has focused on materials relating to modern Greece, thus supporting the University's program in Hellenic Studies, as well as American Judaica presented by Leonard L. Milberg.

The Robert H. Taylor Collection: Placed on deposit in the Princeton University Library in 1972, and received as a bequest in 1985, the Robert H. Taylor Collection consists of more than 4,000 rare books and 3,300 manuscripts illustrating in their wide range the scope of English literature from the 14th-century to the 1920s. The collection began c. 1930 and progressed to its present form in several distinct stages. It was moved to Princeton in 1960 and housed in Firestone Library in 1972.