In the writing of the book Natural Capitalism, we became aware that the smart companies are already implementing the principles of natural capitalism, perhaps, not as a coherent whole. But as they realize that there is a set of four principles—they can implement all of them profitably—this thing's going to take off. And it already is. As Paul Hawkins is fond of saying, 'this train is leaving the station, it doesn't care whether your company's ticket is punched.'—Hunter Lovins.