We live in a time when borders seem to be either crossed easily (by currencies, information, and disease) or almost impenetrable (for displaced persons and migrants). The establishment, reestablishment, reinforcement, violation, and control of borders are common factors underlying many of the most contentious contemporary issues, from Brexit and COVID-19 to the immigration policies of the European Union and the United States. Borders are sites of transience but also of construction, comprising checkpoints, temporary or quasi-permanent shelters, and fortified barriers, among other structures. Given the importance of borders currently and historically, it is essential that our discipline account for the architecture at and of borders. As Anoma Pieris, editor of Architecture on the Borderline, argues in her introduction, the question is “how a discipline and practice deeply invested in nation building might address the violence implicit in territoriality” (1).

The essays in this volume acknowledge this implicit violence, and in doing so, they contribute to a deeper engagement with borderland architecture by taking on the wide variety of its forms and types. The thirteen texts here are arranged into three sections. “Frontier” addresses spaces and structures related to territorial expansion and control. “Boundary” takes on the practical realities of border maintenance, including both licit and illicit means of traversing borders. Finally, “Margin” considers efforts to preserve both tangible and intangible forms of cultural heritage, particularly in cases where clear lines of division—between group identities, for instance—cannot be drawn. The topics covered in these essays encompass a wonderfully broad span of examples from around the world. A map near the book's beginning locates twenty-four sites that are addressed in the pages that follow. The volume's scope is broadly contemporary, although several essays reference historical events, such as the U.S. internment of Japanese and Japanese American citizens during World War II, the Korean War, and an episode of compulsory population exchange between Greece and Turkey in 1923. Multiple disciplinary perspectives are represented, including anthropology and sociology as well as architectural history and urban planning. Accordingly, the sources referenced in the volume range from official reports from governmental and nongovernmental agencies to contemporary news accounts to works by theorists known for their work on space and its control, such as Eyal Weizman, Michel Foucault, and Doreen Massey.

Although the essays feature a variety of examples drawn from across the globe, several themes recur. The concept of visibility and invisibility, not only of borders but also of the various individuals and groups they seek to divide or contain, emerges as a key trope. Borders are sometimes clearly visible—think of a line on a map—but they may also be edge spaces that are not always readily apparent. Pieris's essay on Japanese internment camps, Alessandro Petti's account of checkpoints between Jordan and Israel (in the “Frontier” section), and Irit Katz's chapter on migrant camps in northern France (in the “Boundary” section), for example, all bring much-needed attention to the kinds of impermanent and unseen spaces and structures often found at borders. These essays make clear that at issue in debates about migration is not only the control of space but also the control of its depiction. The contribution in “Frontier” from Sean Anderson and Jennifer Ferng, for example, considers how the European migration crisis of 2014–16 was visualized in the context of the New York Museum of Modern Art's 2016 exhibition Insecurities: Tracing Displacement and Shelter. Data visualizations such as those featured in this MoMA show are one way to materialize what can be difficult or even impossible to photograph, but, as Anderson and Ferng point out, there is also the danger of “desensitisation” (59): too much visual and textual information can generate a glut, whereby overabundance becomes absence. Through their thoughtful treatment of data visualization, these authors highlight its usefulness while also drawing attention to the lack of rigor and standards occasionally at work in its creation and interpretation.

As Anderson and Ferng note, the power of images to represent borders and the spaces and activities associated with them can be limited, with depictions often reduced to focusing on remnants of border-crossing events such as “boats, life vests, camps and deserts” (67) rather than the borders themselves. One reason for this is the fugitive nature of edge spaces and architectures. In her essay “Mapping the War: Everyday Survival during the Siege of Sarajevo,” Dijana Alić describes how dividing lines changed quickly and unpredictably in wartime Sarajevo, writing that they were “invisible although present: the frontline defined the parameters of the city; the shelling from above made movement limited and local; and diverse modes of attack by snipers and artillery rendered the daily engagements uncharted and unpredictable” (142).

Alić's essay, along with others in Architecture on the Borderline, reminds us that borders do not always take the form of physical barriers and can change, multiply, and dissolve or disappear in response to a variety of conditions. Thus, while many well-known borders, such as the one that divided East Berlin from West Berlin and the border between India and Pakistan, might appear to be clear, solid, and almost immutable, the reality of borders is often one of intangibility and arbitrary fluctuation. Borders not only partition nations and geographic regions but can also establish and reinforce social, ethnic, and economic divisions. They often lie at the periphery, yet they sometimes crisscross through the center of a territory. They are also experienced differently by different people. As Petti notes of the Jordan–Israel border, “The border machine is interactive architecture: it changes depending on the citizenship of the person who crosses over it” (79). Shifting power relations and the influence of history on the present have profound effects on the locations of borders and the space and architecture around them. In his account of the redevelopment of Kowloon East in Hong Kong, Daniel P. S. Goh argues that the area “has become one of the new boundaries in Hong Kong's ‘transborder’ cultural politics of a colonial city reintegrating into a rising Chinese nation” (222). The negotiation of past and present through urban planning and architecture is a difficult challenge that will undoubtedly become even more fraught as mainland China continues its attempts to integrate the former protectorate through a gradual erasure of the border separating it from Hong Kong.

Together, the essays in this volume clearly demonstrate the need for and relevance of an architectural history of borders, one that knits together questions of space, planning, and design. Creating such a history is not an easy task. Architectural historians have typically examined buildings through theoretical lenses of cohesion, permanence, and presence, whereas border architecture requires an analytical approach that accounts for contingency and transience, informality and improvisation, materiality and immateriality. However, and as Natsuko Akagawa argues in her essay, “Where Do We Draw a Line? Heritage, Identity and Place in Global Heritage,” “contrary to predictions that globalisation would contribute to international cooperation, today, despite or because of greater mobility, uniformity and commodification of heritage, the desire for the demarcation of identity has, if anything, become stronger” (260). In this context, virtually any work of architecture can be thought of as existing at a border, making the need for volumes like this one all the more pressing.