This second edition of Health Aspects of Aging serves to broaden the perspectives of societal change due to increases in life expectancy, as well as the effects of age-related changes as they impinge upon the provision of health care for older persons. The growing presence of a large number of persons aged 65 and older worldwide has propelled a re-evaluation of the nature of life that is protracted to 100 years and beyond. The emphasis in this second edition is to replace the prevailing problem approach to aging by a problem-solving approach. The problem-solving approach of this volume has allowed for the incorporation of the concept of new social structures and the development of intervention and prevention strategies along with new technologies. Such new products and health care measures include those that are deliberately aimed to offset debilities due to normal age changes, the onslaught of diseases, incongruous environments, and altered social states. Such a multi-disciplinary perspective underscores the fact that aging permeates not only biological systems, but clinical medicine, economics, ethics, and the very fabric of society. The chapters in this volume address these issues from the standpoints of diverse disciplines and professional positions. Since biological changes are primary issues, the aging process is largely described from the perspective of biological changes related to age and to particular dysfunctions. The environmental features and the potential introduction of technological interventions are interspersed within chapters, as well as finding primary focus in particular chapters. The maturity of the technology described in the chapters varies, from devices and systems that are nearly ready to be marketed to concepts and prototypes that are still in the design and developmental stages in the laboratory. The relationship between the provision of appropriate health care and the responsible utilization of technologies as described in this volume will serve to enhance the nature of life extension.