“Urban interstices”—their design—are the topic of this book. What are urban interstices? What different issues, opportunities, roles, and concepts do they deal with?The book’s five chapters written by urban planners, architects and interior designers provide five different views and keys—Urban rewriting, Architectural threshold, Green rooms, Connecting publicness, Ephemeral devices—and draft a possible path to sound the spectrum of urban interstices’ design in Italy. Urban space can be “interstitial” in its ambiguous capability of signification in the sense-making process; that is, in the double valence of a mute void—space without signification—or meaningful room—a small and dense universe of suspension. Sometimes the project for interstitial spaces aims to transform the former into the latter. Sometimes, on the other hand, the project makes the interstice an interface, connector, exchanger, membrane, space of interrelation. So that urban interstices become alternatively thresholds and pulsating rooms, and urban catalysts activated by specific design moves and devices. And somehow they also speak of a general “interstitial” condition of urban space today. The critical path proposed here is based on the review of seventy contemporary Italian cases. A collection of sixty projects is provided in the second part of the book, while ten cases—two for each thematic key—are explored in brief monographic essays and by interviews with the authors of the projects. They are the subject of the photographic essay, Visual narration, put in the middle of the book.