How Healthy Are We? A National Study of Well-Being at Midlife is a compilation of the findings of the Midlife in the United States (MIDUS) study and the culmination of 15 years of work. The original study was funded by the John D. and Catherine T. MacArthur Foundation. This book includes some 20 chapters written by more than 35 contributors, in addition to the editors, who provide an array of topical interpretations and analysis of the data. It is an impressive and lengthy compendium and a valuable contribution to the epidemiology literature, including valuable insights into a range of psychosocial factors that define and affect middle-aged life in our society.

The book's stated objective is to summarize "the rich array of new findings" coming forward from the MIDUS study. By all measures, the book appears to have succeeded in this ambitious goal and as such will be a valuable reference tool for writers, researchers, policy makers, and others who are interested in the issues and needs of this segment of the population.

The book begins by describing midlife as the "last uncharted territory" of the life course and makes a compelling argument for the importance of increased information and knowledge about this overlooked and understudied phase of life. The survey, conducted in 1995, included more than 7,000 English-speaking adults ranging in age from 25 to 74 years, the idea being that respondents aged 40 to 60 years could be readily compared with others in the study cohort. There is an acknowledgment of some selection bias in the sample, but this does not appear to substantially reduce the value or relevance of the findings.

The book is divided into three major sections. The first section provides a focus on physical health; the second examines emotion, quality of life, and psychological well-being; and the third considers contexts of midlife, including work, family, neighborhood, and geographic location.

Age and gender differences in health are key themes. For example, one chapter focuses on menopausal transition and aging processes. In addition, the impact of psychosocial factors and inequities is given careful attention. However, several authors suggest that there are wide variances within social strata such that no single psychosocial factor emerges as a key variable in health for adults in midlife.

The MIDUS findings appear to present a fairly positive portrayal of the psychosocial aspects of aging—older adults had higher levels of positive affect. In contrast, adults at midlife seem to be more heavily influenced by contexts such as work and family, and the importance of good social relationships emerges as a primary factor in the sense of well-being. That ethnic and minority status was a positive predictor of psychological well-being was a somewhat unexpected finding and prompted some speculation as to the overall gains to be made by overcoming the challenges of racism and discrimination.

Finally, the authors contend that with its innovative assessment of daily stressors in a large sample of respondents, the MIDUS study offers perhaps the first national look at social responsibility within family and community life. It is easy to conclude that there are multiple ways in which individuals' emotional and physical well-being are influenced, both positively and negatively, by their experiences at work, within the family, and in the community. Individuals are significant contributors to their families, communities, and workplaces and at the same time are strongly influenced by what is occurring in these life domains.

The implicit challenge of this book and its authors is, How can these data and understanding be translated into social policy, health behaviors, and mental health promotion to better support the well-being and success of individuals as they pass through this phase of life? As the population of the United States continues to age, a better appreciation of the impacts of midlife has the potential to help individuals, families, and society prepare for the needs of this group as it advances into older adulthood.

Dr. Adams is medical director of adult services at the California Department of Mental Health in Sacramento.