On April 17, 1998, the Neurolab Spacelab mission lifted off from Kennedy Space Center. On board were 26 experiments dedicated to studying the effects of weightlessness on the brain and nervous system. Over the course of the 16-day mission, the crew worked through the demanding and complex payload to provide an in-depth and fascinating look at how a basic natural force-gravity-can profoundly affect the nervous system. This book contains the results from the mission. Neurolab's focus on brain and nervous system research allowed for in-depth studies and provided a series of complementary results. Even though performing science experiments in weightlessness presents significant logistical and operational challenges, the guiding philosophy on Neurolab was to surmount operational challenges to meet the science needs, rather than alter the science to meet the demands of spaceflight. As a result, in most cases, the facilities in space on Neurolab were the equal of Earth-based laboratories. Where they weren't equivalent, every effort was made to provide comparable results. Because of this effort, the Neurolab mission provides a remarkable scientific story. This book offers an overview of Neurolab for the general scientific reader. It contains both scientific reports from individual investigator teams and technical reports on some of the noteworthy procedures or pieces of equipment that were developed for the flight. Each major area of study on the flight (the balance system, sensory integration and navigation, nervous system development in weightlessness, blood pressure control, and circadian rhythms and sleep) is described with illustrations and a brief introduction.