With the discovery of a tiny fish in a soon-to-be-flooded stretch of the Little Tennessee River, construction on a dam that had already cost taxpayers $100 million came crashing to a halt. Thanks to the Endangered Species Act of 1973, the snail darter was instantly transformed into both an icon for species preservation and a despised symbol of the environmental movement's alleged excesses. The intense legal battle that ensued over its fate was contested...