This is a paper on economic method and strategy, in which the aim is to apply economic theory to the task of practical development planning in a peripheral regional economy. This is done in the form of a case study on the Northwest Territories (NWT), Canada. There are four main sections. First, the regional context of planning is proposed, leading to the consideration of questions about capital and labour mobility. Second, the case of Plural Economy is examined in theory and in its practical relation to the NWT. A third section deals with determinants and mechanisms of economic growth; multiplier and linkage effects are defined, evidence of their operation is given, and the income and expenditure of government is analyzed. The fourth major part is a draft proposal for an economic model suitable for the NWT which incorporates the foregoing analysis in a modified input-output framework. The paper closes with a variety of suggestions on how to construct a long-term economic plan.