Coral reefs are wonders of nature. Elaborate limestone structures fabricated by innumerable coral polyps no bigger than a pencil eraser, they protect our coastlines, provide sustenance to hundreds of millions of people, and create some of the most complex and diverse ecosystems on Earth. They are also under dire threat, from global warming above all but also from runoff, pollution, and overfishing. The stakes are high and the timeline short, but coral reefs can still be saved—and initiatives around the world are aiming to do just that, from Australia to Papahānaumokuākea to the Florida Keys.

Marine scientist Juli Berwald is a perfect guide to the otherworldly seascapes that corals create, and the necessity of saving them. She is the author of Spineless, a science memoir about jellyfish, and Life on the Rocks, which takes readers to reefs around the world and spotlights research and advocacy efforts to restore their vitality. Berwald received her PhD in ocean science from the University of Southern California, and her work has appeared in Nature, National Geographic, and The New York Times.