With this volume, the Annual Review of Gerontology and Geriatrics celebrates its 10th year of publication. It is fitting that this issue unintentionally takes us back to the basic biology of aging, an issue of fundamental importance even for those with limited knowledge and no specific interest in that subject. The excitement that a scientific or clinical approach to aging generates lies in large measure in the cross-disciplinary nature of the discipline. The aging of human-kind is controlled by the biology of the species interacting with environmental events that affect the length and quality of life. As increasing changes in fundamental biologic knowledge now seem to alter the life span and address diseases that modify the course of one's life, we should examine and understand this substrate of knowledge. The new and growing field of biology, which some call molecular biology, has the potential to change our future with its ability to identify gene structures and to prevent diseases.