Jerry Zaltman's brain is all over the place. One lobe has spilled onto a bookshelf, another has plopped onto a fallen picture frame, and the stem is buried beneath the edge of a half-read manuscript. It's not a pretty sight.

But there's hope. Zaltman eases himself from his chair and begins retrieving the pieces - plastic sections of a life-sized model of the human brain. He glances at each brain chunk and then, in a blur, effortlessly reassembles the whole. In an instant, he's got the brain back together again.

He pauses. And for a moment, he grasps it. Tenderly, Jerry Zaltman grasps the human brain. Which is why some of the biggest, richest companies on the planet have journeyed to his cluttered Harvard Business School office to rethink everything they know about marketing.

Marketing is a luxury of progress. It is necessary only in cultures that have largely satisfied basic human needs. The homeless and the hungry are still among us, but today most Americans have little trouble obtaining the basics: Their world is marked by oversupply in almost every category, from cars to candy bars. The average American supermarket is stuffed with 30,000 different items. Since 1980, the number of products launched each year has tripled; in 1996 alone, companies introduced some 17,000 new products. For sellers, this reality is daunting: How do I stand out? For buyers, it's confusing: How do I get what I want, when I want it? For Zaltman, a few disciples, and a handful of forward-thinking companies, it's an opportunity to reinvent marketing.

The problem, Zaltman says, is that our knowledge of what we need lies so deeply embedded in our brains that it rarely surfaces. Our native tongue is powerless to call it out of hiding; a second, more obscure language is needed. But few who speak to us in the marketplace even know that this second language exists - let alone how to speak it.

"A lot goes on in our minds that we're not aware of," says Zaltman. "Most of what influences what we say and do occurs below the level of awareness. That's why we need new techniques: to get at hidden knowledge - to get at what people don't know they know."

Zaltman invented perhaps the most powerful of these methods. He calls it the Zaltman Metaphor Elicitation Technique - this self-effacing man's only discernible act of ego. But to most, U.S. Patent Number 5,436,830 ("a technique for eliciting interconnected constructs that influence thought and behavior") is known simply as ZMET. The method combines neurobiology, psychoanalysis, linguistics, and art theory to try to uncover the mental models that guide consumer behavior - to illuminate the dark shadows of the customer brain. It is a bilingual phrase book that can narrow the linguistic gap between the marketer and the marketed-to. In other words, in the effort to decode the hieroglyphics etched on the walls of our minds - our emotions, feelings, and fears - ZMET may be the new economy's Rosetta Stone.