Topics for the Beltsville Symposia are selected to highlight specific areas of research and science policy that are of concern to scientists in the Beltsville Area as well as to the general scientific community. Each sympo­ sium in the series is structured to provide a realistic appraisal of current findings, research progress, and relevant policy issues within the constraints established by the organizing committee. Thus, the presentations and dis­ cussions that have marked these symposia have had a strong appeal to the broad community of scientists. Knowledge of the diversity of living organisms is still quite limited. Since the time of Linnaeus, about 1.7 million species have been described. The actual number has been estimated between 5-50 million. Many species, land races, and strains are vanishing. Clearly, the world's scientific institutions are inadequately equipped to attain sufficient knowledge of a significant fraction of the diverse living forms. Also, efforts in the collection and preservation of germplasm of plants and animals urgently need to be strengthened. These mattes are critically important to future generations. This symposium addresses vital concerns of biotic diversity and germ­ plasm preservation from diverse perspectives. Many of the parts provide concrete recommendations for action, and they call attention to areas of research that must be pursued with intensity.