This is the first of a series of thematic volumes consisting of a selection of papers from the XXth International Congress of History of Science, which was held in Liege in 1997. The present volume deals with the relationship between science, technology and politics in the 20th century, with a special emphasis on some areas of the world that recently underwent serious political change including the German Democratic Republic and other countries from the former "Eastern bloc" such as Hungary, Ukraine, the Baltic countries, Russia, and countries in Central Asia. Individual contributions from Japan, Algeria and Portugal have also been included, since they should help initiate a transnational reflection on the subject.