This chapter tells the stories of the work of three men who, together with Geddes, can be considered the founding fathers of contemporary planning. They worked in different contexts – in Catalonia and England – and at different times – from the mid-nineteenth century to the first half of the twentieth century. The first is the story of the plan of Barcelona, which is also the story of the construction of a planning theory founded on spatial models and rules. The second is the story of a small project for social reform through the construction of a new city, a “Garden City,” which was to be extended to the region in the “Social City.” The third is the story of the Greater London Plan 1944, which develops Howard’s insights and applies them to a large urban region. These three plans share a common thread in that they all use space to draw out profiles of social citizenship: the first implicit; the second the fruit of almost involuntary actions; and the third explicit and conscious. Even without making specific reference to the idea of citizenship, the three authors – the Catalonian Cerdà and the Englishmen Howard and Abercrombie – construct three forms of social citizenship by organising and regulating space.