Five hundred and fifty-seven sharks. Every one of them matters. For four hundred million years, sharks have shaped the ocean. They outlasted five mass extinctions, watched the dinosaurs come and go, and built the ecosystems that produce half the oxygen in the atmosphere and feed more than a billion people. Now, more than a third of all shark species are threatened with extinction — and most of them have never appeared in a documentary, never been photographed in the wild, and never been given a name the public knows. Every Shark in the Sea changes that. Drawing on current taxonomy, population assessments, and decades of field research, D. M. Gross profiles every known living shark species — from the eighteen-meter whale shark to the seventeen-centimeter dwarf lanternshark — with the depth, rigor, and narrative drive that each one deserves. Part One covers shark biology in full: how they sense, hunt, reproduce, navigate, and communicate — the vocabulary you need to understand everything that follows. - Part Two moves through all eight living orders, species by species and family by family. The great white receives the treatment its complexity demands. So does the frilled shark, the cookiecutter, the goblin shark, and the dozens of deep-sea lanternshark species whose names most readers will never have encountered. No shark is reduced to a footnote. - Part Three makes the case for the ocean that cannot exist without them — the habitats, the crises, the economics of conservation, the interventions that are actually working, and a practical final chapter for readers who want to do more than read. This is not a field guide. It is not a scare sheet. It is, as completely as any book can be, an introduction to every shark alive on this planet right now — and an honest account of what we stand to lose if we allow the decisions being made today to continue without the knowledge this book provides. For anyone who has ever stood at the edge of the ocean and wondered what is moving through the dark below.