In Lincoln's day a President's religion was a very private affair. There were no public prayer meetings, no attempts to woo the Religious Right. Few of Lincoln's countrymen knew anything at all of his religious beliefs.

Lincoln had no such person that he could talk with. Often, as a result, he debated with himself, and he would draw up a kind of list of the pros and cons of an argument, and carefully figure them out, and he might test them in public.

Lincoln was not a good impromptu speaker; he was at his best when he could read from a carefully prepared manuscript, though maybe a teleprompter could have helped that!

I was able to sit at Lincoln's side and see how he thought and how he acted, and how he felt about what was going on around him. I felt the pressures that were on him. You can see what people were writing to him, how they were nudging him.

I'm not sure Lincoln would fare well if he were a presidential candidate today.

The big biography of Lincoln necessarily had to do so much with his political career, his ambitions, his accomplishments in public, with less time to spend on his private life, his inner life, and I thought this might be a way of getting at that.

The more I have studied Lincoln, the more I have followed his thought processes, the more I am convinced that he understood leadership better than any other American president.