The LuEsther T. Mertz Library is one of the world's largest and most important botanical and horticultural research libraries, with over one million accessioned items (books, journals, original art and illustration, seed and nursery catalogs, architectural plans of glass houses, scientific reprints, and photographs) and over 4,500 linear feet of archival materials. The Library serves as both a research and a public library and as both a scholarly resource and a general plant information service. It offers a wide array of reference resources, print and electronic, and the help of an informed staff to anyone visiting the Library through the Internet or in person.

The Library seeks to collect as comprehensively as possible in systematic and floristic botany with particular strengths in the literature about the Western Hemisphere, the focus of the Garden's research program. Since its establishment in 1899, other major research and academic libraries in New York City have transferred their plant-related collections to the Library and have deferred to it the role of serving as the primary plant-focused library in the metropolitan area.

The Library is an active institutional member of the Research Library Group, the Council on Botanical and Horticultural Libraries, the Society of American Archivists, and the American Institute for Conservation.

As part of its digitization efforts, the Library is a major contributor to the Biodiversity Heritage Library.

For more information, please visit the Mertz Library and The New York Botanical Garden.