Imagine harvesting pure sunlight to use as fuel, while turning carbon dioxide into breathable oxygen—this is what a leaf does every day. And it isn't just for plants: Corals partner with photosynthetic organisms to create the most productive habitat on Earth, slugs eat chloroplasts as natural green camouflage, and hornets use photosynthesis as a means of air-conditioning. Detailing just how it works, biologist Raffael Jovine also shares how we ourselves might harness the power of photosynthesis to repair ecosystems, stabilize the climate, and grow more food sustainably.