Wal-Mart, with its legendary focus on customer value in terms of price, is innovating in sustainability. Now, we're beginning to see the mirror image, a convergence, as the not-for-profit sector is beginning to serve more effectively by applying private sector accountability and efficiencies to social needs. This reflects a rising recognition that to serve others best requires more than good intentions; it mandates a focus on real-world results. Bill Gates and Warren Buffett are among the most conspicuous advocates and representatives of this transformation.

Some critics have suggested that Ronald Reagan succeeded in a series of careers, ultimately as a two-term president of the United States, by a series of fortunate accidents. Such a criticism is not backed by the evidence. It is true, though, that Reagan's approach to work and life was not conventional.

Ronald Reagan memorably combined intimacy with distance.

Curiously, for all the outpourings of scholarship on Theodore Roosevelt, no one had written a book focused directly on his leadership approach, working in large part from his own letters and other writings. That opportunity was open, and I was privileged to step in.

William Ewart Gladstone is credited with the credo that a prime minister must be a "good butcher." The metaphor is apt insofar as the root of the word "decision" is "to cut."

Woodrow Wilson is reported to have told a Princeton colleague, shortly after the 1912 election, "It would be an irony of fate if my administration had to deal chiefly with foreign problems, for all my preparation has been in domestic matters." In the event, Wilson's early months were marked by substantial domestic legislative accomplishment. Unfortunately, after Europe plunged into the Great War in August 1914, Wilson's leadership was uncertain.

Often, in a given project team or network, one sees leadership roles shifting among various members at various times. Attempts to fit these into traditional views of "leader" and "follower" don't quite work. It's more like Twitter: the "leader" has "followers" - but the "followers" are empowered to alter the relationship unilaterally, and the "leader" must continually earn the consent of the "followers."