In his introduction to Utopia Forever: Visions of Architecture and Urbanism, Lukas Feiress asks, “What is it that makes a utopia worthwhile, regardless of its potential applicability in reality? Is it not, perhaps, this inapplicability that is at the heart of utopia’s inspiration?” Of the 49 cities on display in this sumptuously illustrated book, only a few are even remotely feasible. Le Corbusier’s Radiant City, for instance, allowed for both high population density and an abundance of green space and natural light through a parklike ground plane crisscrossed with elevated walkways. Most designs are more fanciful, such as Multiplicity, a quilt of fields draped over Melbourne, Australia (supposedly to be completed in 2110), and Dead Websites Archive, a Borgesian library miles above Croatia where you can access an infinitude of deactivated websites. Not a single detail of these designs is likely to become reality during our lifetimes, but that’s not the point. The question for these architects and futurologists isn’t what can we build, but, as Buckminster Fuller put it, “How big can we think?” • $68; Die Gestalten Verlag, May 2011.