This volume has contributions from the United States (3), Russia (2), and Europe (4). These contributions include investigations of biological problems encountered in spaceflight by humans, animals, plants, and single cells, as well as studies of a fundamental biological problem aided by space experiments. Two extensive chapters attempt to determine the mechanisms of the effects of long-term space missions on the human body (Grigoriev and Egorov, Russia), and the adaptative mechanisms operative in the human body under these conditions (same authors). Other chapters deal with ultrastructural observations of myocardial deconditioning (Philpott et al., United States), fluid and electrolyte regulation (Gharib and Hughson, France/Canada), human nutrition in space (Hinghofer-Szalkay and Konig, Austria), growth and cell division in plants (Krikorian et al., United States), mechanisms of the effects of gravity on single cells (Mesland, The Netherlands), orbital exobiology studies of the origin of life (Hornech and Brack, Germany/France), and my own contribution on the use of chemical sensors for space biomedical research and monitoring of water recycling.