It is just before dusk on a September evening in Nashville, Tennessee, at the Opryland Hotel, a colossal antebellum theme park of a hotel--thousands of guest rooms, soaring enclosed tropical gardens, life-size indoor replicas of southern mansions. At 10 minutes before the first plenary session of this particular therapy conference, the huge Presidential Ballroom is already packed with 3,300 professionals here for the four-day meeting, and latecomers like me are climbing over rows of knees to get to the few remaining seats. While giant screens on either side of the stage list upcoming regional conferences and workshops--in Philadelphia, Chicago, Orlando, Kansas City, Dallas, …