The book which you are holding is the result of 20 years of research carried out in Russian Institute for Biomedical Problems (Moscow) established at the dawn of the space era to provide medical and psychological support to space flights. It offers a survey of speech analysis methods together with a detailed description of the authors' choice of the methodological basis which they used in their study of the isolated small groups' communication with the outside world. The research outcomes obtained in a series of simulation experiments conducted by international space agencies allowed the authors to identify the basic regularities in the communication of people performing professional activity in long-term isolation and confinement. The method was used to study communication of cosmonauts and astronauts working on International Space Station. The stages of the pilot research and of the method capabilities verification are also described in this book. The book should be of interest to communication specialists, psychologists and medics.