The University of Nebraska Press editions of The Journals of the Lewis and Clark Expedition are widely heralded as a lasting achievement. In all, twelve volumes and a comprehensive index are projected, which together will provide a complete record of the expedition. Volume 12 contains the most complete listing of the plant specimens cataloged by the Lewis and Clark expedition. All but one of the plants were collected by Meriwether Lewis, the most skilled botanist among the expedition’s members. The collection, however, was nearly lost over the years due to its scattering among various botanists who intended to catalog the expedition’s scientific discoveries. Fortunately, for many years the specimens have been in the care of major institutions, principally the Academy of Natural Sciences in Philadelphia. The 239 extant items are brought together here for the first time. This invaluable volume will assist researchers and enthusiasts hoping to identify each plant’s location, distribution, and use along the expedition’s route.