The Herbarium of the Field Museum of Natural History contains 2.5 million mounted specimens with concentrated coverage of Central and South American areas, and is the fifth largest repository of plant specimens in the western hemisphere. The Herbarium is actively expanding its holdings through the research and survey activities of its Curators, through exchanges with other herbariums, and through donations of private collections. Botanists from around the world rely on access to the specimens in the Herbarium which are made available to visiting investigators and through loans. The Museum has initiated an ambitious plan to construct new collection storage areas for the Herbarium, and this will relieve crowding in the collection, allow currently inaccessible specimens to be processed and made available, and provide room for many years of collection growth. Dr. John Engel, Chairman of the Museum's Botany Department, has devised a three-year plan to make all backlogged specimens available, and to implement the first phase of transition to the newly constructed collection area. Collections of natural history specimens such as the Field Museum's Herbarium are critical resources for the study of biological diversity on Earth. Continued growth and improvement of these resources is essential for current investigations into ecology, evolution, global change (among other areas of inquiry), and for future generations of researchers.