We have entered the Planetary Phase of Civilization. Strands of interdependence are weaving humanity and Earth into a single community of fate—the overarching proto-country herein christened Earthland. In the unsettled twenty-first century, the drama of social evolution will play out on a world stage with the perils many and dark premonitions all too plausible. 

Still, a Great Transition to a planetary civilization of enriched lives and a healthy planet remains possible. But how? What forms of collective action and consciousness can redirect us toward such a future? Who...