The publication of these proceedings, held in Warsaw, Poland, represents an exchange agreement between the two sponsoring organizations to build better lines of communication on criminological subjects between Eastern Europe and Western nations. Participants are mainly researchers and educators from Eastern European countries, with a few representatives of Western Europe. Among the topics covered are the effects of prison sentences on convicts' recidivism rates, the relative effectiveness of voluntary versus obligatory postrelease assistance, definitions of recidivism and specific preventive measures in Polish law. Also reported are the problems of postpenal measures in East Germany and Czechoslavakia, the legal concept of recidivism in Czechoslavakia, the system of preparation for release from prison and postpenal measures in the USSR, and psychosocial problems of exconvicts. Some notes, tables, and bibliographies are included in the separate articles. For individual papers, see NCJ 70487-99 and 70501-02.