(FORTUNE Magazine) – Is it really only a year ago that a dozen Burger King managers at a retreat burned their feet walking over hot coals in a team-building exercise?

Sigh. Business consulting was a hoot during the fat years. You could tell an executive to do just about anything. And you didn't have to know much about business.

Today a new rigor is called for. In these pages you'll meet three big thinkers--a strategist, an architect, and a scholar--who have bold ideas about the world. Yet radical as they may be, they never lose sight of economic reality.