This work deals with the logic and functioning of international seaport administration. It is not only a reference for public and private port administrators and managers but can offer, by its international comparisons, insights for the deregulation, privatization, liberalization and deconcentration of former government duties. Every seaport hosts different port activities in which public and private actors interact in changing relations. There is a permanent question of how responsibilities among public port administrators and the private users of the port have been divided and institutionally anchored. The model of analysis used in this research has been built up by the distinction in four different control relations between state and market. By means of this institutional model the division of responsibilities for nautical control, port planning and port services can be determined. The reader can also learn via this model about the specific conditions that are needed to activate the learning capabilities of the different port activities. The model of analysis can be applied to every seaport in the world.