ince 1947, Percy Schmeiser has been more than a Canadian canola farmer. He and his wife Louise have been seed developers, saving year to year the best of their crop, slowly breeding seed adapted to the Saskatchewan plains and, more particularly, to their own acres. But all that ended with a surprise letter. One day in August 1998, the Schmeisers received notice from Monsanto. It accused the farmers of "stealing" Monsanto's patented seed, Roundup Ready — a genetically modified version of canola that survives spraying of the popular herbicide Roundup — that the company had found on the Schmeiser...