Book excerpt: How humanity brought about the climate crisis by departing from its evolutionary trajectory 15,000 years ago—and how we can use evolutionary principles to save ourselves from the worst outcomes. Despite efforts to sustain civilization, humanity faces existential threats from overpopulation, globalized trade and travel, urbanization, and global climate change. In A Darwinian Survival Guide, Daniel Brooks and Salvatore Agosta offer a novel—and hopeful—perspective on how to meet these tremendous challenges by changing the discourse from sustainability to survival. Darwinian evolution, the world’s only theory of survival, is the means by which the biosphere has persisted and renewed itself following past environmental perturbations, and it has never failed, they explain. Even in the aftermath of mass extinctions, enough survivors remain with the potential to produce a new diversified biosphere. Drawing on their expertise as field biologists, Brooks and Agosta trace the evolutionary path from the early days of humans through the Late Pleistocene and the beginning of the Anthropocene all the way to the Great Acceleration of technological humanity around 1950, demonstrating how our creative capacities have allowed humanity to survive. However, constant conflict without resolution has made the Anthropocene not only unsustainable, but unsurvivable. Guided by the four laws of biotics, the authors explain how humanity should interact with the rest of the biosphere and with each other in accordance with Darwinian principles. They reveal a middle ground between apocalypse and utopia, with two options: alter our behavior now at great expense and extend civilization or fail to act and rebuild in accordance with those same principles. If we take the latter, then our immediate goal ought to focus on preserving as many of humanity’s positive achievements—from high technology to high art—as possible to shorten the time needed to rebuild.