Edmund Morris has spent over 20 years writing about Theodore Roosevelt. Theodore Rex is the second book in a projected trilogy about the great man's outsized life.

Theodore Rex is the second volume of your proposed biographical trilogy of Theodore Roosevelt. How was the writing of it affected by the 21-year hiatus between books?

He's a real luxury to write about. There are few characters who are inexhaustible: Wagner, de Gaulle, Churchill, Napoleon, Theodore Roosevelt—these are characters you can never lose interest in because they are so encyclopedic. I had to put this second book aside when I started doing Dutch, the book on Ronald Reagan, in 1985. When I was through with my 14 years on Reagan, I was amazed at how quickly I came back to Roosevelt. He's just that vivid a personality.

Does the authorial voice change because of the type of material you're handling?

In this volume, the authorial voice is gone, unlike Dutch, where it was on every page. TR just fills the page and needs no interpretation.

Because TR wrote so much, leaving behind one version of his own life story, do you come to this with an agenda, intending to change the point of view he left behind?

Every single document ever written by somebody presents a point of view the writer wants preserved, whether it's mendacious or otherwise. TR happened to be, luckily for me, one of the most honest people that ever lived and was a literary machine who turned out hundreds of thousands of letters, manuscripts, books and articles. But there are moments in his life where there is a vacuum.

Is it difficult being foreign-born [Morris was born in Kenya] and going back in time to recover a sense of that era? Or does it offer advantages?

The same things that an American takes for granted, I don't. As a biographer it helps to have a slight edge. I've always been tormented that the past is irretrievable. In writing about a great figure such as TR, it's about wanting to capture that time in all its color and detail. My first Roosevelt book begins with a re-creation of January 1, 1907, when TR held a White House reception and I went back and plucked that day out of time. That challenge is the single most powerful urge I have as a writer: to bring back the fleeting.

Do you see your role then as a historian, as well as a biographer?

I'm interested in what he did and how he did it and in trying to come to terms with his peculiar brilliance. He had all of Bill Clinton's political and improvisational brilliance. At the same time, he had all the diplomatic expertise of a Richard Nixon. As one of his own predecessors, Grover Cleveland, said of him, "He was the most perfectly equipped politician to ever enter the White House."

Do you think T.R. would have good advice for Bush at this time?

I don't know if I can answer speculative questions like that. A more modern response would be to say that he could certainly follow Ronald Reagan's advice to his father, George Sr.: "Do a lot of saluting."

In the wake of McCullough's John Adams becoming a bestseller this summer, is there something about this point in history that's motivating people to read presidential biography?

I think that at any time America is in crisis, we instinctively develop the need to read about substantial figures, substantial presidents who have embodied the United States. To read about a great president is to read about ourselves and understand our country better. So I think it's understandable that people should be turning to figures like Adams at a time like this; it's a time of national self-examination.