The Metropolitan-Hinterland Thesis is a theory of historic relations between a large, powerful urban community (metropolis) and the surrounding territory (hinterland) which the metropolis dominates through mainly economic means. Formulated by economic historian N.S.B. Gras in the 1920s, since the 1950s it has been widely applied and extended in Canadian history to illuminate the growth of urban power, REGIONALISM and the general interplay of central and territorial forces. Gras conceived 4 stages in the rise of a major city to metropolitan dominance: it first harnessed the commercial life of a wide adjacent territory, then centered its industrial activities, built up its transport network and finally provided financial services to, and so more controls over, the hinterland. Later, it appeared that these were better regarded as key attributes of economic metropolitanism than as stages operating in straight sequence. The concept was also widened to include noneconomic aspects such as the political power wielded by metropolitan centres, especially as seats of governments, or the social, cultural and informational holds they may acquire. In any case, metropolitan-hinterland relations remain reciprocal, producing complementariness as well as confrontation in complex patterns that may involve whole sets of urban centres, as well as overlapping, changing hinterlands.