Predicting the future of the city is a lot like predicting the future of human society. Urban areas embody the physical infrastructure of our cultures and economies, and will house 70 percent of the world's population by 2050. They are too complex for detailed extrapolations, yet we can make insightful observations about their current behavior.

For example, in 1991 Saskia Sassen popularized the term “global city” to indicate a metropolis that is a critical node in the global economy. That definition stuck, but now urbanists, policymakers, and programmers are heralding the new “smart city.” The premise is simple: a smart city integrates hardware and software to improve living and working conditions. However, the broad debate on what “smart” means in practice only proves that the endgame scenario is still unknown.

Multinational companies like Cisco, IBM, and Siemens are all promising that their proprietary urban hardware and software will make cities more efficient, desirable, and competitive in the global marketplace. Universities are opening smart-city labs and institutes to study the phenomenon. Independent programmers are working to produce the next smart-city killer app. Change is certainly coming: the World Bank predicts a $30-to-50 trillion investment in urban infrastructure worldwide in the next 20 to 30 years. So how will cities decide what to implement? What factors should they consider and prioritize?

The City as Interface and Smart About Cities try to answer those questions in different ways. The former offers a broad survey of smart-city technology and an exploration of how individuality and community will balance out in the city of the future. The author, Martijn de Waal, an assistant professor at the University of Amsterdam and cofounder of the urban and digital media research group The Mobile City, offers a book that's heavy on academic terminology from sociologists, architects, and media gurus past and present. There are no illustrations or diagrams beyond its eye-catching cover. Instead, the book is littered with questions that articulate what is at stake but offers frustratingly little prognostication.

De Waal understands that even a robust accounting of current technology and social thought cannot forecast the future with certainty. However, one can't help but feel disappointed that he didn't imagine some future urban scenarios to enliven and conclude his academic labors. What would Hannah Arendt, Marshall McLuhan, or the Archigram group see in Songdo, a brand-new city in South Korea built with smart-city hardware and already home to 70,000 residents? Will its urban data collection become politicized? Might residents rise up and offer alternatives? Instead of synthesizing his philosophical investigations with his survey of technology and policy to bring new ideas to the field, he concludes that “my aim here has been to make a start on this philosophical exercise” and that a future “generation of test cases” will translate that philosophy into practice.

Conversely, the editors of Smart About Cities—Maarten Hajer and Ton Dassen—argue that sustainability should be central to the ongoing smart-city discussion. Hajer is a public policy professor and director general of the Netherlands' strategic environmental and planning policy institute. Dassen and many chapter authors also work at the agency as researchers, though some have architectural backgrounds and are joined by two contributing designers. They argue that urban technology will be the infrastructure of human society and, consequently, that cities should be seen in terms of the global production and consumption of natural resources.

Its chapters read like a data-driven urban Whole Earth Catalog, with each section providing an executive summary and essential statistical information for a specific subject (Demography, Air, Water, Food, Cargo, Energy, etc.). Its slick charts and vibrant graphs—showing the sheer volume of kilometers of travel, kilograms of waste, and gigajoules of energy—demonstrate that the vaunted city-of-the- future must be built with the global ecological crisis in mind. “Our urban metabolism is literally hidden,” writes Hajer. “Visualizing the urban metabolism shows what current city life entails and gives us a sense of what decoupling,” i.e. the creation of a sustainable metabolism, “would require” in the near future.

Both books approach the subject from a very Dutch perspective. Sometimes de Waal's thoughts on community and individuality feel too rooted in Dutch history, while much of the Smart About Cities data is, despite its global argument, focused on the Netherlands. The books strain to match local data and history to global rhetoric, suggesting the obvious: despite their interconnectedness, the world's cities will become “smart” according to their own idiosyncratic economic, cultural, and political circumstances.