While we normally regard a city's core as the main object of urban history, Kristin Poling encourages us to regard the urban frontier as an important site of study. Perhaps even more than the city center, the outskirts and suburbs of cities were a site for imagining and planning the urban future. In particular, Poling focuses on city walls in the nineteenth century (although by that point they were often surrounded by suburban development) as the locus for debates over urban growth and change, along with some discussion of the development of the suburban fringe. Poling challenges the commonplace notion that removing walls led to urban growth, indicating that the relationship worked in reverse: urban growth led to the removal of city walls.

The revolutionary and Napoleonic wars rendered city walls obsolete, Poling points out, and between 1791 and 1815, 350 German towns and cities razed theirs as a sign of the times. Yet in many places, including major German metropoles, city walls remained standing well into the nineteenth century, raising questions about their cost and purpose. City councils generally championed the removal of walls, whose maintenance often fell on municipal shoulders, while other actors at the local and state levels generally sought to retain them as tools of local control. By the late nineteenth century, historic preservationists joined the debate with their calls to preserve city walls as emblems of the past.

Poling has organized her book as a series of case studies, examining Leipzig, Oldenburg, Paderborn, Berlin, Nuremberg, and Posen/Poznań either in stand-alone chapters or in separate sections within shared chapters. While this range of case studies is admirable, representing several different regions and types of cities, Poling does little to bind these cases together, with little systematic comparison within the chapters and only a brief conclusion. She might have better organized the book with thematic chapters drawing examples from the different case studies, highlighting the similarities and differences between them. As it stands, it is left to the reader to identify the commonalities running between the cases as well as their distinctiveness.

A common story emerges. Big cities like Leipzig and Berlin appear to have witnessed many of the same struggles as backwaters like Oldenburg and Paderborn. Where city walls remained into the nineteenth century, they continued to function as tax boundaries, with excise taxes collected at the city gates. (This begs the question, how did cities without walls extract these taxes?) Even as municipal boundaries expanded beyond the old walls, as they did in Leipzig and Berlin, cities erected new barriers—often just wooden fences—to control access. City councils, presumably dominated by liberals, complained about the limits to the free circulation of goods and people, light and air, imposed by city walls. They chafed at the costs of maintaining these structures and sometimes purposefully let them decay. The poor conditions of city walls, along with the poverty and unsanitary conditions that surrounded them, constituted a common source of complaint—leveling these structures, city councils argued, would provide room for cleaner and healthier alternatives such as promenades, Ringstrassen lined with civic buildings on the Viennese model, and/or better housing. Indeed, city walls became a symbol of backwardness, with the commercial city of Leipzig finally mobilizing to remove its walls in the 1830s, following the publication in Dresden (its aristocratic rival) of a satirical portrayal of the city huddled behind its medieval walls. Modernizers also prevailed in the Prussian east. In the distinct case of Posen/Poznań, calls to remove the city wall reflected a desire to prevent the Germanized city from becoming disconnected from the Polish countryside, with plans for “German” single-family homes and increased access to nature to make the city more welcoming to Germans.

Those seeking to retain city walls invoked the need to collect excise taxes at city gates, but also cited the desire to keep undesirables (vagrants, prostitutes, and, one imagines, also political dissidents) out of the city. At the same time, city walls often demarcated an important social divide between those with privilege inside the walls (including guild monopolies and access to municipal services like street lighting) and working-class suburbs outside. Maintaining a wall between these populations helped to police this divide (not unlike the gated suburbs of today). Given the social importance of city walls as well as their use by insurgents, it is surprising that the Revolutions of 1848 hardly make an appearance in the book.

Later in the nineteenth century, as the state abolished excise taxes collected at municipal borders (such as the Prussian Slaughter and Mill Taxes, instituted in 1810 and lifted in 1873–1874) and surviving city walls increasingly lost their purpose, these massive stone structures became monuments of municipal history. Instead of being denigrated as medieval relics impeding progress, city walls were now celebrated by historic preservationists as emblems of a proud Renaissance past, when sober civic leaders presided over a flourishing urban economy. The mid-nineteenth century witnessed a rising interest in the Holy Roman Empire, and Nuremberg—one of the old empire's capitals—became the focus of this attention, with a campaign in the 1870s to save the city's intact walls. The Bavarian government and historic preservationists, both local and national, mobilized to block an alliance of liberals, progressives, and socialists from removing the walls.

Poling moves outward from city walls to consider the broader urban frontier in a chapter on Berlin. Berlin's rapid growth in the 1870s as well as its new status as imperial capital made its sprawling suburbs the focus of national anxieties about urbanization. Shantytowns emerged near burgeoning centers of industry, where landowners could not erect Mietskasernen (rental barracks) fast enough to meet the enormous demand for housing. In an engaging analysis, Poling explores the way the press embraced these shantytowns as emblems of a German frontier spirit, with their denizens, who might have otherwise emigrated to the Americas, instead engaged in a suburban form of inner colonization, fashioning for themselves communities that expressed their individualism and desire for orderly neighborhoods. These shanties stood in stark contrast, in the press' imagination, to the anonymous rental barracks, denigrated as “stone tents” for nomadic workers, who formed no stable communities as they shuffled between one dreary cubicle and another in their frequent moves across the city. The chapter also makes some reference to Schrebergärten (allotments), villa colonies, and forests on the edge of Berlin, but their treatment is fairly brief.

Poling limits her study to Germany in the nineteenth century, although more background on the significance of walls in earlier periods would have provided important context for understanding the conflicts she explores, and she is wholly silent on the legacy of these debates for urban planning in the twentieth century. Readers also would have benefitted from a discussion of what exactly rendered city walls obsolete as well as why walls had been removed from some cities around 1800 but not others. At the same time, since Poling sees the urban periphery as a site for imagining the future, she surprisingly does not address the actual German future as it played out in the twentieth century. In what ways did the debates about city walls in the nineteenth century help shape urban development in the twentieth? At what point did city walls turn from a sign of backwardness and an obstacle to development into valuable tourist attractions? Notably, the Berlin Wall of the twentieth century escapes mention altogether, despite striking parallels with Berliner youth chiseling openings in the city walls in the 1860s to create unauthorized gates. Moreover, the book could have benefitted from more comparisons with cities beyond the frontiers of the Kaiserreich. Why did so many more British and French cities, as Poling notes in passing, lose their walls? Was the persistence of city walls in Germany a sign of greater political conservatism, as Hugo Preuss suggested? Poling's book draws our attention to debates about city walls and the suburbs that lay outside them, but fails to place these developments into larger context.