This monograph offers information, suggestions, and proposals to teachers, students, and citizens to increase their understanding of the aging process in both its physical and psychosociological aspects. Part I, What Is Aging? examines various aspects of aging, some of its major characteristics, and what it is like to grow old in the U.S. today. Part II is concerned with the physical aspects of aging: how the body changes; the aging processes of human cells, human tissue, and organ systems; aging and disease; some theories on why aging takes place; and suggestions on how to deal constructively with aging. Part III examines some psychosociological aspects of aging, with emphasis on ways to encourage continued psychological and social involvement with the rest of the world. Appendixes provide details of resources for additional information. Appendix A describes programs for senior citizens, specifically those provided by ACTION and the Department of Labor. Appendix B lists materials available free from the Administration on Aging. Appendix C gives the locations of all regional and state agencies on aging. (MBM)