The idea for this special issue, exploring the history of cities and urbanism within the emerging transnational paradigm, originated in a discussion among the members of the North American Editorial Board of Urban History about what it means for cities to be global.Footnote ¹ Veering in many directions, spanning multiple centuries and stretching into much of the world, the conversation touched on the movement of people and ideas, the relationship of urban areas with their hinterlands and with each other, the importance of given technologies and industries for particular forms of urban development, the critical role of politics – at all levels – in that development and the ongoing and evolving role of global capital on those cities. Using the global Internet, members of the North American Editorial Board located in Montreal (Michèle Dagenais), Rochester (Victoria Wolcott), Irvine (Jeffrey Wasserstrom), Philadelphia (Lynn Hollen Lees), Miami (Robin Bachin), Mexico City (Hira de Gortari Rabiela), Hamilton (Richard Harris), Los Angeles (Philip Ethington and Janice Reiff), Amherst (Max Page) and Ann Arbor (Matthew Lassiter) generated a plan to issue a global call for papers for the IXth International Conference of the European Association for Urban History in Lyon, France in August of 2008. Nine scholars from Canada, the United States, France and Mexico pre-circulated their papers for a special bilingual double-long session, co-chaired by Michèle Dagenais and Phil Ethington.

These papers considered transnational connections across four continents, with the only requirement that American cities played some role. Intensive conversations about one another's papers, and about the integrity of the frameworks used, resulted in a jointly produced position paper after the conference, which was used to guide the further revision of the papers that now appear in this special issue of Urban History. Although three of these initial eleven scholars are not represented in this issue, Jeffrey Haynes (University of Oregon), Jorge Rivera Páez (UNAM) and Janet Stevens (UCLA) made tremendous contributions to the collective effort to challenge, refine and expand on the various notions of transnational and urbanism.

Was it necessary, some asked, to apply the adjective ‘transnational’ at all? Are not cities places where transnational flows and connections – among people, culture, practices, trade and even infrastructure – have usually been commonplace, especially those that were founded in the Americas as European colonies? What is the difference between considering the practical, experiential transnationalism of goods and people in global circulation, on the one hand, and the self-conscious transnationalism of international planning organizations such as the Congrès International d'Architecture Moderne (CIAM), or the European Association for Urban History, on the other? We asked about the significance of international power asymmetries (with the United States as hegemon) in the Americas, and the ongoing importance of ‘the national’ for cities, politically, socially and culturally. And, how important were the global, regional and local scales that contemporary ‘global city’ theorists emphasize, and how did the balance between these scales evolve over time? These and other questions that arose during the Lyon meeting shaped how the authors whose works appear in this issue revised and refined the articles collected here. Each brings their own rich research and interpretation into a dialogue with each other and with the larger set of ideas emerging as historians grapple with the concepts of transnational and globalization.

Three of the essays – those by Pierre Chabard, Ellen Shoshkes, and Clément Orillard – engage those questions by focusing on the emergent practices of urban planning and urban design. Chabard's ‘Competing scales in transnational networks: the impossible travel of Patrick Geddes’ Cities Exhibition to America, 1911–1913’ captures a particularly revealing moment in the evolution of city planning in both Europe and the United States by examining efforts to bring the Cities and Town Planning Exhibit (CTPExh) to the United States. Created from national and international exhibits on display at the 1910 Royal Institute of British Architects’ Town Planning Conference and Exhibition and the personal collection of Patrick Geddes (the head of the CTPExh planning committee), the exhibit captured in sprawling visual form the many ideas circulating internationally about planning and urban reform. This exhibit was displayed primarily in the United Kingdom until 1913 when it appeared at the Ghent International Exhibition.

In documenting the ultimate failure to bring CTPExh to North America, Chabard provides insights into a number of ways in which the transnational, the national and the municipal informed the professionalization of planning, especially in America. At the same time, he offers the opportunity to see how the strategies of urban reformers and city planners relied on international contacts, both to validate themselves professionally and to achieve their more local goals. As he does, Chabard highlights the role of familiar players on both sides of the Atlantic, men like Patrick Geddes, Raymond Unwin, Benjamin Marsh and Frederick Law Olmstead, Jr.

In her essay ‘Jaqueline Tyrwhitt and transnational discourse on modern urban planning and design, 1941–1951’, Ellen Shoshkes, in contrast, uses the career of British town planner, editor and educator Jaqueline Tyrwhitt to explore the creation of a transnational scholarly community concerned with sustainable urban design. The daughter of a British architect who worked in places as diverse as South Africa (where she was born) and China, Tyrwhitt was widely travelled even before she chose to study regional and town planning in the 1930s. Her background, interests, innovative ideas and, as Shoshkes argues, her ability to be ‘the woman behind the man’ to several famous figures such as José Luis Sert and Sigfried Giedion made her a key, if not yet well-enough-known, player in the revival of a transnational dialogue on post-war urban reconstruction.

Tyrwhitt's activities during the years 1941–51 on which Shoshkes focuses serve as a valuable window into a decade critical for understanding both the evolution of urban design and the reorganization of international power and influence. Strongly influenced by Geddes’ bioregionalism and by European modernism as articulated by CIAM, Tyrwhitt spent the war years as the research director of the British Association for Planning and Regional Reconstruction developing, first, interdisciplinary survey techniques that could be used in rebuilding after the war and, subsequently, organizing and running a Correspondence Course in Town Planning for members of the armed forces. Her achievements in that position earned her a prominent place in the international discussion on post-war redevelopment and her articulation of town planning as a comprehensive discipline encompassing, as Shoshkes describes it, the region, the neighbourhood, work, food, health, education, transport, leisure and holidays made her and her ideas increasingly influential. Following the war, she participated actively in the creation of the emerging academic discipline of urban design in the United States, in the post-war planning and reconstruction efforts of the new United Nations, and in the leadership of CIAM. In her careful presentation of Tyrwhitt's personal and professional networks, Shoshkes not only demonstrates the critical role Tyrwhitt played in shaping and sharing ideas about regional planning and design; she also points to the emerging new economic and political geographies that arose in the aftermath of World War II that would shape future exchanges.

Clément Orillard also takes note of those new, post-war geographies and networks, even as he deploys a very different strategy to uncover and highlight transnational urbanism. Rather than employing a particular prism through which to focus a complex web of relationships, his essay ‘Tracing urban design's “Townscape” origins: some relationships between a British editorial policy and an American academic field in the 1950s’ offers an important new telling of the origins of urban design that strays dramatically from the familiar story of the translation of CIAM ideas about urbanism into the context of American higher education, a process made easier by the recruitment of many of CIAM's leading practitioners to academic positions in the United States. His is a story of how two ideas on different sides of the Atlantic – Architectural Review's ‘Townscape’ editorial policy and Harvard Graduate School of Design's Urban Design Conferences – were parallel productions of an emerging new context in the intersecting spheres of architecture and planning. In documenting the more complex story, he reminds his readers of two developments that shaped that new context. The first was the transformation of CIAM from an international organization to a transnational organization that began as émigrés from continental Europe fled to Britain and the United States, continued through the war and was formalized in 1947. Accompanying that evolution was the organization's growing emphasis on urban form and aesthetics, an emphasis visible in Tyrwhitt's urban constellation design that Shoshkes discusses. The second was the growing importance of universities, NGOs (in this case the Rockefeller Foundation) and the popular press (here Fortune magazine) in shaping the debate over planning and architecture in the United States.

In documenting how ideas, as encapsulated in both words and evocative images that represented the visual qualities of urban spaces, moved easily across the Atlantic, Orillard demonstrates how they were transformed in their own national contexts. As he so effectively argues in comparing their implementation in Britain with that in the United States, these ideas were ‘not about urban renewal but post-war rebuilding; not about Gottman's megalopolis but the destruction of the historical English landscape; not about shopping malls but new towns that were almost totally absent from the US context’.

Although they diverge widely in approach and, in doing so, provide valuable models for writing transnational urban history, each of the three articles already discussed speaks most directly to what can best be described as an Anglo-American planning milieu. Nicolas Kenny, in his article ‘From body and home to nation and world: the varying scales of transnational urbanism in Montreal and Brussels at the turn of the twentieth century’, returns us to the beginning of the twentieth century and situates the question of transnationalism in a Francophone context. Using Montreal and Brussels as his sites, Kenny examines how a common global discourse about bodies, cities and their relationship to each other made it possible for that discourse to be shared by reformers, planners and residents in these relatively unconnected locales at the edges of the Anglo-American landscape. Reminding us that individuals experience the city through their bodies, he focuses our attention on the ways in which public health, hygiene and sanitation – all intimately related to individual bodies – were critical issues in forging a transnational urban dialogue in the waning years of the nineteenth century.

Building convincingly on Patrick Joyce's contention that ‘the care of the city and care of the body become as one, just as the health of the city and health of the body were one’, Kenny explores the ways in which that common understanding ‘seeped’ into the discourses of his two chosen cities in areas as diverse as housing and sewers. As he does so, he focuses our attention again on the importance of the municipal as compared to the national in fin-de-siècle transnational exchanges. Equally important, he demonstrates that direct communication and contact were not necessary for ideas and policies to move from one city to another. Participating in what Kenny describes as ‘the many threads of an elaborate, multidirectional web’, reformers, planners and residents in Montreal and Brussels engaged in a common rhetoric and sought similar solutions.

Nathan Connolly's ‘Timely innovations: planes, trains and the “whites only” economy of a Pan-American city’ relocates us to Miami, Florida, to explore transnational urbanism from still another innovative perspective. Starting from the position that racism was a material building block of American urban life, Connolly looks at the ways in which segregation serves as a kind of technology that shapes Miami as much as the trains and planes – other technologies that helped to transform the city into a global metropolis.

Miami's location – inside the United States and in relation to the Caribbean – is critically important to the city's development and to Connolly's argument. Jim Crow segregation was already incorporated into Florida law and practice when Miami was incorporated in the last decade of the nineteenth century but would, as he shows, grow stronger in the first decades of the twentieth century. Those segregated practices, written into state and municipal law, not only separated blacks and whites spatially in the city. They also made money for those investing in the growing city – profits were higher for landlords in Miami's segregated neighbourhoods than for hotel owners in the beach-front areas that brought white tourists to the city. But others classified as non-whites came to Miami as well, and they are an important part of Connolly's larger argument. Migrants from the British West Indies came to Miami for jobs and for relief from the colonial practices that shaped their lives at home. So did African American entertainers who, like the West Indians, had to abide by those rules.

Even as segregation was branding Miami as a Southern city, another technology was intervening to make it an important Pan-American city – the airplane. Beginning in 1927, Pan-American ‘Clippers’ joined the city to other ports around the Caribbean. Eight years later, the company secured landing rights that connected Miami to Mexico and many locales in South America. Many of the people who came to Miami on those Pan Am flights – government officials and well-to-do tourists from racially mixed Caribbean and Latin American countries – challenged the structures of segregation simply by their presence. Important international visitors who, because of their race, were excluded from Miami's segregated accommodations created a dilemma for corporate and local officials intent on marketing the city as a Pan-American metropolis. These boosters had to find private solutions that maintained Miami's colour line while providing these visitors with housing, services and the respect their visitors’ positions demanded. More publicly, these boosters honoured the whitest of Latin American patriots and heroes with statues and named spaces and streets. Not only did these transnational exchanges change Miami, they changed the way Miamians and other Americans constructed acceptable images of their nearest neighbours based on their own racial beliefs.

Leandro Benmergui's article, the only one of this collection that focuses specifically on South America, also serves to weave together the many themes that emerge from the other articles and their distinctive approaches to transnational urbanisms. His focus is on the struggle for decent housing in Rio de Janeiro and Buenos Aires that was one of the key targets of the Alliance for Progress, a programme for regional co-operation announced by the United States in 1961. In placing this effort within the larger discourse of what he describes as a ‘new transnational modernizing sociological and urban discourse on the urban home’ that organized urban space and domestic life, Benmergui's article echoes certain of the insights into transnationalism that appears in Kenny's piece situated 60 years earlier. It is also a very different story because it is shaped by the efforts of United States government to use an array of institutions, from universities to foundations to international funding organizations, to shape the direction of development of its Alliance partners, their countries, their cities and their people. Utilizing the concept of contact zones, sites of transculturation ‘built by multivocality, by negotiation, and by unstable borrowings’, Benmergui demonstrates how public housing in Rio de Janeiro and Buenos Aires, built with international financing to improve living conditions and modernize residents, served instead as sites of cultural exchange and political negotiation.

The rapid growth of Latin American cities in the 1950s and 1960s, the spread of favelas, economic conditions and political instability that made it difficult to absorb the growing populations drew the attention of scholars, planners, policymakers, lending agencies, philanthropic agencies and international organizations and government. As these groups from South and North America came together in conferences and projects and shared ideas through papers and correspondence, contact zones were formed that identified housing as a transnational concern within a larger modernization framework. But, as Chabard, Orillard and Kenny all demonstrated, those contact zones did not guarantee what Benmergui describes as ‘literal translations’. Rather ideas were challenged, reformulated, disputed and selectively appropriated. They also took their local forms. In Rio de Janeiro and Buenos Aires, the discourses took on their own sometimes subtle, sometimes starkly different shadings. Local and national politics influenced where housing was built and what it was named. Architectural styles ranged from CIAM-inspired high-rises to small individual homes. The hopes for what housing could accomplish for individuals and Brazilian and Argentinean society were strikingly similar. So were the problems the housing left unresolved, not only in Buenos Aires and Rio de Janeiro but even in the US cities in which so many of the experts sent from there lived.

This brief introduction serves only to identify some of the major strands that link the articles collected here, but many more specific linkages, shared historical personalities and interlocking concepts will be found within the pages of each article. These cross-references, cutting across the boundaries of these articles as they did through the porous boundaries of nation-states, are further explored in the Multimedia Companion to this special issue, to which we refer the readers: www.journals.cambridge.org/urbanhistoryextra.