The Northern Sea Route (NSR) through Russia's ice-infested Arctic waters can potentially halve sailing distances between Europe and Northeast Asia. It also passes by some of the world's largest oil and gas reserves. As we enter the 21st century, technological, political and even climatic developments are again making the NSR an interesting possibility. The International Northern Sea Route Programme (INSROP) has enlisted the expertise of 450 researchers from 14 countries for six years to answer the questions: Is international commercial shipping on the NSR feasible - economically, technically and environmentally? And if so, under what conditions? The problem is obviously complex and so the programme adopted a multi-disciplinary approach, with 104 sub-projects mapping and investigating relevant ship technology, costs and benefits in relation to other transport routes, potential impacts on the environment and local indigenous peoples, cargo potential, political and administrative obstacles, availability of insurance, security aspects, jurisdiction and environmental law, and other aspects. The results and conclusions of the 104 studies have been integrated and are presented here. This reference work should be of interest to commercial and political decision makers concerned with the development of NSR shipping, as well as other stakeholders and interested experts.