The missions of the early space age--when a relatively few, very highly trained, physically fit male, pilot/astronauts operated for short times--will be supplemented in the future by missions where large numbers of nonpilot/astronaut men and women will work in orbit for long periods of time on research and industry-related tasks. The lengthening and changing complexity of space operations requires that the psychosocial, habitat design, food systems, and economic aspects of humans working in space be reviewed carefully. In this volume, an interdisciplinary group of experts addresses these aspects of space work and delineates avenues for future research.