While acknowledging the profound impact our species has had on the natural world, and rivers in particular, Rewilding the Urban Frontier: River Conservation in the Anthropocene argues that this new age in which humans have inexorably modified the planet presents opportunities for rethinking our relationship to the natural world and potentially healing the age-old rift between humans and nature. More than any other ecosystem, urban rivers typify our evolving relationship with nature. Once a necessity for the development of civilization, by the twentieth century, America’s rivers became neglected and abused, channelized, dammed, filled with sewage, and toxic waste. But then, spawned by America’s rising environmental awareness, the Clean Water Act of 1972 initiated a clean-up of the nation’s waterways. Fifty years later, most of America’s rivers are “fishable and swimmable” once again. But along with river revitalization, America has also experienced an explosion in urban growth such that our natural ecosystems are highly fragmented and disappearing under asphalt and concrete. Yet, urban rivers provide crucial wildlife corridors and connectivity to core conservation areas and offer opportunities to connect to the natural environment. Done right, rewilding urban rivers can help forestall biodiversity loss and address environmental and social inequities.