<p> Periods of great social change reveal a tension between the need for continuity and the need for innovation. To comprehend these changes as history and as guideposts to the future, Peter F. Drucker has, over a lifetime, pursued a discipline that he terms social ecology. The writings brought together in <em>The Ecological Vision</em> define the discipline as a sustained inquiry into the man-made environment and an active effort at maintaining equilibrium between change and conservation.</p>