Wars have been fought over it, revolutions have been spurred by it, national diets have been based on it, economies have depended on it, and the settlement of North America was driven by it. Cod, it turns out, is the reason Europeans set sail across the Atlantic, and it is the only reason they could. What did the Vikings eat in icy Greenland and on the five expeditions to America recorded in the Icelandic sagas? Cod -- frozen and dried in the frosty air, then broken into pieces and eaten like hardtack. What was the staple of the medieval diet? Cod again, sold salted by the Basques, an enigmatic people with a mysterious, unlimited supply of cod. Cod is a charming tour of history with all its economic forces laid bare and a fish story embellished with great gastronomic detail. It is also a tragic tale of environmental failure, of depleted fishing stocks where once the cod's numbers were legendary. In this deceptively whimsical biography of a fish, Mark Kurlansky brings a thousand years of human civilization into captivating focus.