Some years ago, the planning group at Shell surveyed 30 companies that had been in business for more than 75 years. What impressed us most was their ability to live in harmony with the business environment, to switch from a survival mode when times were turbulent to a self-development mode when the pace of change was slow. And this pattern rang a familiar bell because Shell's history is similarly replete with switches from expansion to self-preservation and back again to growth.

Arie P. de Geus, "Planning as learning." Harvard Business Review, March/April 1988: 70-74.