This report examines the scientific merits and value of research on human genetic or genomic variation and the organizational, policy, and ethical issues that such research poses in a more-general context than the proposed HGDP (Human Genome Diversity Project). Chapter 2 discusses the scientific basis and usefulness of a worldwide systematic survey of human genetic variation. Chapters 3 and 4 address technical and logistical problems posed by such a project with respect to sampling design, obtaining and maintaining sufficient genetic material, access to research materials and information, and data handling. Chapter 5 examines ethical, legal, and social issues. Chapter 6 treats the organization of the project and research priorities.