WASHINGTON – A conversation with Sen. Barack Obama, whose book, “The Audacity of Hope” (Crown Publishers, $25), has just been released.

Q. Why did you decide to write this book? What is your writing routine?

A. I decided to write it partly on the heels of my (2004 Democratic National Convention) speech, which had gotten a good response. I thought it would be interesting to think about what I’d been saying in the campaign and subsequent to the campaign. Basically I didn’t start writing until after I’d served about six months in the Senate because it was so overwhelming. I would typically work in the evenings after I got home from work or tucked my girls into bed, and on the weekends. I’m a night owl. I’d jot notes into my computer when I got home.

Q. How was writing this different from your first book? (A 1995 memoir, “Dreams From My Father: A Story of Race and Inheritance,” which was reprinted in 2004.)

A. The first book was much more introspective. I was digging into sort of my past. It was more a book of self-discovery written by a young man. This book was more a rumination on the country and where we need to go.

Q. What will be the effect on Congress if Democrats recapture the House of Representatives or the Senate?

A. We would see greater oversight over the administration’s actions. And I think we would start talking about the issues I hear most often on the campaign trail: health care, education and energy.

Q. Why did you pick legislation on government accountability, co-sponsored with one of the most conservative Republicans in Congress, Senator Tom Coburn of Oklahoma, as your first bill?

A. There are all sorts of other bills I’d love to have passed (expanding college grants and health care) but when you’re in the minority you have to be opportunistic and pass whatever bills you can get. Tom is the best kind of conservative because he’s a sincere conservative…He’s not just trying to score political points. We all have an interest in making sure our money is well spent.

Q. What’s your greatest fear or self-doubt as a politician?

A. My greatest fear, I think, is that I lose track of that voice: who I am and what my values are and what I care most deeply about. Meeting ordinary Americans and listening to them goes a long way in terms of keeping me grounded, as do my wife and two kids.

Q. You write in your book about the guilt or self-doubt you have about being there enough as a husband and father. Do you feel this question is resolved for you or still in flux?

A. I don’t think you ever resolve it entirely. This is a job that requires a lot of travel, and I miss my kids and I miss my wife all the time.

Q. How long have you been a cigarette smoker? How much do you smoke and have you planned to quit?

A. I smoked for a long time and quit, and occasionally I lapse back into it. It’s an ongoing struggle.