“The Persuaders” explores how marketers try to sell products---and political candidates---in an increasingly cluttered advertising landscape, using increasingly “spiritual” and “big concept” approaches. Assessing what it all means is CBS and NPR media watcher Douglas Rushkoff, who wades through a thicket of psychobabble and manages to make sense of most of it. As for conclusions, however, all he can do is quote an industry aphorism: “I know I'm wasting half my ad dollars. I just don't know which half.”