The medicinal properties of plants have been of interest to society for centuries and continue to be a subject of modern research. Yet too often research has been predicated upon poorly identified plant material and secondary sources of information. Much of what we know about the use of plants as drugs, poisons, foods, and as instruments of magical or religious practice derives from lore inherited from the clay tablets and papyri of the ancients and from compilations of early Greek, Arabic, and Indian physicians. Meanwhile, information pertaining to plant parts used even now in the daily life of peoples far removed from the influence of modern medical and health practices has been largely overlooked. With the encroachment of civilized cultures on primitive societies, unique traditions—often unwritten—are being destroyed. In many instances, the very plants involved are disappearing. Not infrequently, the only record, where one exists at all, of these vanishing pools of knowledge is that of the botanical field worker. For no matter what chemical or biological investigations may follow, the botanist can affix to an actual specimen, as he collects it in the field, the local terms applied to the plant and a description of native medicinal or other uses. Dr. Altschul has compiled field notes of health and medical interest on over 5,000 species of plants, culled from some 2,500,000 specimens of higher plants collected by field botanists from all over the world and deposited in the combined collections of the Arnold Arboretum and Gray Herbarium of Harvard University. The resulting catalogue represents a unique approach to supplying new investigational leads to researchers seeking biologically active plant principles. Dr. Altschul's meticulous sheet&ndashby–sheet examination of the Harvard collections provides the pharmacognosist, pharmacologist, and others in the medical and health sciences with an extensive firsthand survey of the domestic medicines of many cultures. These previously unpublished botanists' notes are here made available in a comprehensive publication that should become an important resource for every investigation into the area of medicinal phytochemistry. Indexes to families and genera are provided, as well as a medical index referring to diseases and to therapeutic properties for researchers intent on locating plants with special medicinal capacities. The author is a Research Fellow at the Botanical Museum of Harvard University.