Singers: Passionate and Sloppy

Janis Joplin is hooked. She has to turn on almost every night. "I'm on an audience trip," she says. "When I go on stage to sing, it's like the 'rush' that people experience when they take heavy dope. I talk to the audience, look into their eyes. I need them and they need me. Sex is the closest I can come to explaining it, but it's more than sex. I get stoned from happiness. I want to do it until it isn't there any more."

"My message," she says, "is 'Get off your butt and feel things!' " When she...