The Plimpton Library of 16,000 volumes covers what the collector called "our tools of learning” from the fifteenth to the late nineteenth centuries. The cataloged books are indexed in the card catalog. There are a good number of uncataloged books, which are classed in Dewey, and findable through a shelflist and an author catalog.
The collection is particularly strong in the "liberal arts" - grammar, rhetoric, arithmetic, algebra, geometry, geography, astronomy. Many of the arithmetics, one of the great collections of sixteenth century arithmetics in the world, are described in D.E. Smith's Rara Arithmetica. The collection of handwriting manuals is one of the finest anywhere.
Plimpton Collections subject guide contains additional information about our Plimpton collections, which include medieval and renaissance manuscripts, Arabic manuscripts, cuneiform tablets, and hornbooks.