This thesis establishes the concept of affective form as a means of examining urban design – being the intersection of architecture, planning and landscape – in relation to techniques of governance. Affective form broadly describes a built environment where people are encouraged to amend, or govern, their actions according to particular socio–political ideas. Exploration of the concept’s application as a theoretical tool is undertaken here in order to generate a means of discussing the ethical function of urban design. The emergence of notions of affective form will be located in the eighteenth century, alongside the growing confidence in the ability for humankind to effect social and cultural progress. In a series of examples, stretching throughout the twentieth century, the implicit relation of planning, architectural and landscape form to social effect is discussed. The language, and design models, used to delineate affective form are described, alongside discussion of the level of intentionality apparent in the conceptions of urban form’s social effect. Critique through affective form allows an analysis that brings together the underlying utopian elements of projects – the traces of ideology and sociological theories – with an evaluation of the formal concepts projected. As the second area of investigation, the city of Perth in Western Australia provides a contextual focus for the examination of concepts of affective form. Through a series of appropriations of urban design models a suburban archetype emerged in Perth of a planned, homogenous field of low–rise, single–family, detached dwellings within a gardenesque landscape. The process of appropriation is described as a continuing negotiation between local expectations and the implicit conceptions of affective form within the imported models. Connecting the two primary concerns of the thesis, the ability of form to influence social change and the evolution of Perth’s garden suburb ideal, is the association of that developing garden suburb model with notions of affective form. The associations are outlined through three case studies. The first is an account of the planning of the City of Perth Endowment Lands Project during the 1920s. The second describes the planning and architecture of the athlete’s village built for the VIIIth British Empire and Commonwealth Games held in Perth in 1962. The third study details the development in the 1990s of Joondalup, a satellite city in the Perth metropolitan region. The account of Perth’s garden suburb ideal is intertwined with the consideration of the varying ways in which the conceptualization of affective form has been expressed. Each case study is contextualized by a preceding chapter that discusses the particular conceptions of affective form used in its examination. Thus the main body of the thesis comprises three parts – each associated with a case study, each containing two linked chapters