Book excerpt: This text deals with psychological, psychiatric, and psychosocial issues that affect people who live and work in space. Rather than focusng on anecdotal reports and ground-based simulation studies, it emphasizes the findings from psychological research conducted during actual space missions. readable text has previously been found only in scientific journal articles. Topics that are discussed include: behavioral adaptation to space; human performance and cognitive effects; crewmember interactions; psychiatric responses; psychological counter-measures related to habitability factors, work-design, selection, training, and in-flight monitoring and support; and the impact of expeditionary missions to Mars and beyond. universities; medical students and residents in psychiatry and aerospace medicine; human factors workers in space and aviation professions; individuals involved with isolated environments on Earth (for example, the Antarctic, submarines); aerospace workers in businesses and space agencies such as NASA and ESA; and anyone who is interested in learning the facts about the human side of long-duration space missions.