Relationship between states, their courts and other public authorities is based on the principle of territoriality and principle of sovereignty. Judicial authority of courts is inseparably connected to the territory of its country. In civil proceedings, it is sometimes necessary to obtain evidence in, or to serve a document on a foreign citizen, in another country. Foreign courts can be asked to help to provide information on address of a witness or other person, information from some public registry etc. This chapter analyzes the relevant legal sources in this area, from the point of view of the Czech Private International Law Act.