Our overall goal has been to understand and plan for human psychological and social adjustment to space. To do this, we have attempted to assemble and integrate information that bears on human performance capability, psychological health, and social and organizational adaptation as they relate to space, and to indicate those areas in which additional research could further ease the Earth/space transition. Although there have been observations, analyses, and experimental studies that bear upon the human aspects of extended spaceflight, the connections and interrelationships among these strands of evidence have not been satisfactorily explored. Our purpose, then, was to seek these connections and, by imposing some order on them, examine holistically the issues of humans in space.
Past attempts to address the overall needs of space travelers have generally involved assembling articles covering a range of topics from a number of well-known specialists. The primary advantage of this approach is the high level of expertise brought to each individual topic; the limitation is the lack of an overall perspective. Since our purpose is to provide an overall perspective, our approach is one of integration rather than compilation. Although the present work builds on, and we hope extends, the earlier work, breadth is necessarily purchased at the expense of depth, and our treatment is that of the informed generalist rather than the topic specialist.
 The goal of promoting a better understanding of human adjustment to space subsumes three major subgoals. The first subgoal is to provide a conceptual outline for organizing the personal and interpersonal dimensions of spaceflight. Although in a few cases our ordering is somewhat arbitrary, our chapter headings and subheadings represent our solution to this problem.
Our second subgoal is to achieve some semblance of balance between two extremes which presently dominate discussions of man in space. At one extreme are the experimental efforts which examine a single or very small number of variables. At the other extreme are the sweeping, often Utopian, views which pay only limited attention to the results of behavioral research. We sought to strike a balance by taking a more comprehensive view than the former approach, and a more research-oriented view than the latter. To this end, we reviewed an abundance of literature, including many studies which were not previously identified as pertinent to the human side of life in space. In addition to the volumes compiled by topical experts mentioned above, we drew from scholarly books and journals covering a broad range of disciplines, and to a significant extent, from the report literature Where information was unavailable in published form, personal communication was sought.
Our third major subgoal was to examine the needs of humans in space, and to suggest research areas that could contribute to our understanding of how to satisfy these needs. Our assessments of needed research are presented in the various chapters, and in the section entitled Directions for Future Research, we outline what we feel are, overall, the most salient research issues.