One of the greatest misconceptions about Theodore Roosevelt - in his time and ours - is that he was impetuous.

Ronald Reagan was notably able to avoid having personal considerations dissuade him from taking decisive actions. This may have arisen in part from his career in motion pictures; it may be related to his being a bit of a loner; it may have related to his focus on those people and principles he sought to serve. What is clear is that this capacity enhanced his effectiveness. It was also a surprise to many people.

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.

Woodrow Wilson administration ended in tragedy, with his insistence on governing following his disabling stroke. I suspect President Wilson is often graded on a special curve, because many academic historians identify with him as one of their own.

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.

Theodore Roosevelt is a natural choice for leadership education. Along with many other observers, I believe he was among the greatest of leaders to serve as president.

Presidential leadership is best evaluated not on the basis of one's agreement with the policies, but on their effectiveness in using their powers to transform the nation and our understanding of ourselves.