About being in the middle: Conceptions, models and theories of centrality in urban studies.

The (dis)advantages accrued by centrality, by being in the middle, is a pivotal causal mechanism explaining the existence of cities and inter-city relations. This chapter introduces classical theories of centrality and elaborates some of the theoretical controversies surrounding them. Four theories are discussed: The von Thünen-Alonso land use theory, Christaller's variety of central place theory, developmental and critical renderings of centre- periphery theory, and urban networks theory. Although antecedents are often much older, these foundational theories developed strongly in the 1950 and 1960s as abstract models in relative space characteristic to that era. Such theories travel easily, but only provide crude pictures of the underlying geographic detail. Although abstract models have long been out of fashion in geography, this chapter argues that they can still make important contributions to contemporary urban thinking. As the different centrality theories have often got tangled up and hybridised over time, their differences need to be disentangled first.