At a time when Europe is growing together, cooperation between countries is becoming increasingly necessary. One of the main reasons for pursuing transnational spatial development is to attain a common understanding of the facts of spatial planning. Hence, the INTERREG III B project"COMMIN" sought to establish a common communication basis for the exchange of knowledge and experience in spatial planning and thus to foster and develop this understanding in the Baltic Sea region. Therefore, on the basis of a standardized structure the COMMIN project partners prepared basic information about institutional settings and spatial planning systems and compiled a glossary of key terminology in spatial planning accompanied by a varying range of fact sheets with respect to planning cases taken as examples. The readers will now find on www.commin.org the whole range of information covering the respective national languages as well as English translations, although in some countries official translations for these issues were lacking. The project partners were aware of the fact that each translation requires a balancing act between legal precision and communicable classification and, at the end, is a question of definition power and of different senses for semantics. The German text on hand (status December 2006) one information package out of eleven was prepared by a team comprising planners, lawyers, economists, and administrative academics. Actually no other publication treating this subject in English exists and it will hopefully contribute not only to understanding planning issues in Europe but also to transferring in this respect information and knowledge within the country. Anyway, being aware of differences between countries is a point of departure for the mutual understanding process.