The world’s oceans are changing at a drastic pace. Beneath the waves and along the coasts, climate change and environmental degradation have spurred the most radical transformations in human history. In response, the people who know the ocean most intimately are taking action for the sake of our shared future. Community scientists track species in California tidepools. Researchers dive into the waters around Sydney to replant kelp forests. Scientists and First Nations communities collaborate to restore clam gardens in the Pacific Northwest. In At Every Depth, the oceanographer Tessa Hill and the science journalist Eric Simons profile these and other efforts to understand and protect marine environments, taking readers to habitats from shallow tidepools to the deep sea. They delve into the many human connections to the ocean—how people live with and make their living from the waters—journeying to places as far-flung as coral reefs, the Great Pacific Garbage Patch, and the Arctic and Antarctic poles. At Every Depth shares the stories of people from all walks of life, including scientists, coastal community members, Indigenous people, shellfish farmers, and fisheries workers. It brings together varied viewpoints, showing how scientists’ research and local and Indigenous knowledge can complement each other to inform a more sustainable future. Poignantly written and grounded in science, this book offers a narrative perspective on the changing oceans, letting us see how our relationships to the oceans are changing too.