In 1947, when J. I. Rodale, editor of Organic Gardening, declared, "the Revolution has begun," a mere 60,000 readers and a ragtag army of followers rallied to the cause, touting the benefits of food grown with all-natural humus. More than a half century later, organic farming is part of a multi-billion-dollar industry, spreading from the family farm to agricultural conglomerates, and from the supermarket to the farmer's market to the dinner...