PW: You won a Pulitzer for your biography of Truman. How was writing the biography John Adams different?

DM: With this book there was no one to interview, there's no photography and no newspaper reportage, to which we are accustomed, which is a vast difference. The quality and quantity of the letters makes up for the lack of reportage, and John Adams's diaries are very revealing. It was an excess of riches for a biographer. I had never worked in the 18th century, and as I tell my wife, I like it there so well I may never come back.

PW: But because you have no firsthand knowledge of the 18th century, did you have to start researching from scratch to develop a context?

DM: One of the fundamental requirements of writing good history or good biography is to see things in the context of the time in which they happened, the culture, the emotional ecology, if you will, in which it happened. Not just to know, but to feel what it was like to live in the 18th century. What was it like when smallpox or yellow fever swept through a city? What was it like to go from Boston, Mass., to Philadelphia on horseback in the dead of winter, when there were no bridges over the rivers between the two cities? I've spent a good part of the last six years trying to read what John and Abigail Adams read. People like Samuel Johnson, Defoe and Swift, and Tobias Smollett, or Voltaire. It's just marvelous, the quality of the prose and the quality of the thinking.

PW: You're trying to recreate a feeling for yourself of what it might have been like to live in that period?

DM: Yes. You have to remember that the people who were caught up in the action of times past have no more sense of how things will come out in the future than we do now. I think it is essential to discover why things happen as they do, why things happened the way they did. Nothing was preordained or on a track. The more ways that one can find in tactile fashion to bridge the divide between our time and theirs, the more helpful it is. I try to go everywhere possible that I can to where things happened and to go at the same time of the year when things took place. John and Abigail Adams wrote well over 1,000 letters to each other. The key to the excitement of this book for me is that John Adams, more than any other of the characters in the American Revolution, takes you into his confidence and tells you more about his inner life, his feelings, than all of them. So it is possible to know Adams far better than anyone else of that time.

PW: The letters provided you with the core of your material?

DM: This is some of the most wonderful material I've ever had to work with. The Adamses left us so much. It's a biographer's dream because you can get below the surface of their lives, which is almost impossible ordinarily. Because the Adamses' letters were written on rag paper in the 18th century, the letters are in as good shape as they were when they were written. He lived longer than anyone in our history and had more to say. He was a great talker, whether on paper or in life.