This volume is concerned with the role of science in fishery management. While this has traditionally been considered as largely a biological problem with clear biological objectives, close examination suggests that management decisions are largely controlled by political, social and economic considerations, biologically constrained. The biologist now has the task of reducing the uncertainties of the venture rather than determining its priorities or its allocation of benefits. The uncertainties arise in part because of lack of understanding of the ecological systems involved, the limited availability of critical information, and the unpredictability of driving forces. The volume reviews the assumptions and simplifications of fishery models, examines the decision making framework in fishery management, and compares management practices in North America, Japan, and Northern Europe. A compilation of fishery management objectives in international agreements and U.S. laws is included.