A century ago management consultant Frederick W. Taylor helped many manufacturing businesses significantly improve their productivity by firmly establishing a rigid managerial hierarchy with "brains at the top, hands at the bottom." Indeed, under Taylorism, actual thinking or initiative on the part of "the hands" was discouraged as potentially undermining the leadership of "the brains."

Whatever its origins—and the connection with historic religious and military hierarchies is obvious—this concept of "unshared leadership," the classic singular leader reigning atop a "command-and-control" hierarchy, remains deeply embedded in Western culture. But as the concept of the knowledge worker began to emerge in the latter half of last century, new evidence appeared that demonstrated the superior performance of a variety of alternatives to hierarchical, directive leadership. Such terms as "emergent and co-leadership," "empowerment and self-leadership," "self-managing work teams," and "servant leadership" began to appear in the literature.

Shared Leadership: Reframing the Hows and Whys of Leadership, edited by Craig L. Pearce and Jay A. Conger, is a collection of 14 essays that attempts to pull together the current state of knowledge about the notion of leadership, not as a series of characteristics or abilities of individuals at the top of the organization but as a dynamic function that emerges out of the relationships of numbers of people who are bound together by some form of group task or goal. The editors are recognized academics who are solidly grounded in research that is relevant to their topic, and they coauthor the introductory and concluding essays. Indeed, for readers who are pressed for time, reading these two essays alone will be rewarding.

Searching the Web, one soon realizes that although the notion of shared leadership is still a relatively new concept, it is already something of a movement. This movement appears also to be falling into what I call the "either-or exclusiveness" trap—that is, the tendency of a new concept to discredit ideas that came before it as wrong or obsolete. In this context several essays in Shared Leadership take a refreshing position of "both-and inclusiveness."

Indeed, one essay in the book is a critique of the shared leadership movement. Although the authors claim that research on this concept remains in the earliest of stages, one emerges from reading this book with the impression that what is really going on is a broadening and enrichment of knowledge surrounding the concept of leadership, the art and practice of influencing groups of people to move toward a common vision or purpose. "Shared leadership organizations" in fact retain accountability hierarchies, but these hierarchies behave much differently than Taylorism's "brains." Those at the top have what Daniel Goleman calls "emotional intelligence," an appreciation of and ability to work effectively with the relational aspects of getting work done. Hierarchies persist in the information age, but the more successful organizations are likely to be those that can mobilize leadership behaviors and skills among not just a few workers, but a majority.

As a final thought, the concept of shared leadership may be particularly relevant to health care, a field in which command-and-control hierarchies have never been prominent. Shared Leadership: Reframing the Hows and Whys of Leadership is rich in ideas that might help health care's highly interdependent managers and caregivers work together more effectively in today's high-stress health care environment.

Dr. Merry is adjunct associate clinical professor of health management and policy at the University of New Hampshire in Exeter.