The present book summarizes parts of the research made in the Norwegian Multispecies program. This program was initiated by the then Norwegian Council of Fisheries Research, which was later integrated in The Research Council of Norway. Modelling has been a key element in the program. In the first place, modelling, be it singlespecies or multispecies modelling, is an efficient way of summing up existing knowledge, and performing analyses of different types on the basis of it. Further more, models may serve as a meeting ground between fishery researchers from differ ent academic fields. This...