Our relationship with the ocean is undergoing a profound transformation. Just three decades ago, nearly everything we ate from the sea was wild. Today, rampant overfishing and an unprecedented biotech revolution have brought us to a point where wild and farmed fish occupy equal parts of a complex and confusing marketplace. We stand at the edge of a cataclysm; there is a distinct possibility that our children's children will never eat a wild fish that has swum freely in the sea.

In Four Fish, award-winning writer and lifelong fisherman Paul Greenberg takes us on a culinary journey, exploring the history of the fish that dominate our menus ' salmon, sea bass, cod, and tuna ' and investigating where each stands at this critical moment in time. He visits Norwegian megafarms that use genetic techniques once pioneered on sheep to grow millions of pounds of salmon a year. He travels to the ancestral river of the Yupik Eskimos to see the only Fair Trade'certified fishing company in the world. He makes clear how PCBs and mercury find their way into seafood; discovers how Mediterranean sea bass went global; challenges the author of Cod to taste the difference between a farmed and a wild cod; and almost sinks to the bottom of the South Pacific while searching for an alternative to endangered bluefin tuna.

Fish, Greenberg reveals, are the last truly wild food ' for now. By examining the forces that get fish to our dinner tables, he shows how we can start to heal the oceans and fight for a world where healthy and sustainable seafood is the rule rather than the exception.