When I began work on my first book, 'The River of Doubt,' which tells the story of Theodore Roosevelt's 1914 descent of an unmapped river in the Amazon rainforest, I thought of it as a tale of adventure, exploration and extraordinary courage.

If uncovering the truth is the greatest challenge of nonfiction writing, it is also the greatest reward.

I have always been interested in the idea of self-reinvention.

With the Lincoln assassination, the South didn't feel it could mourn along with the North. But Garfield was beloved by all the American people. He was trusted and respected by North and South, by freed slaves and former slave owners. Also by pioneers, which his parents had been, and by immigrants.