Open your refrigerator door, and you summon forth more light than the total amount enjoyed by most households in the 18th century. The world at night, for much of history, was a very dark place, indeed.

Every twenty minutes on the Appalachian Trail, Katz and I walked farther than the average American walks in a week. For 93 percent of all trips outside the home, for whatever distance or whatever purpose, Americans now get in a car. On average the total walking of an American these days - that's walking of all types: from car to office, from office to car, around the supermarket and shopping malls - adds up to 1.4 miles a week, barely 350 yards a day.

I wish I could adjust my voice, but it's just what's happened to me. It's because I've lived abroad for a long time, and my wife is English and my kids all have English accents, and every voice I hear is English. I've never intentionally changed my accent at all.

I really enjoy going to a library and spending the day doing research - to me that is the most pleasurable part of writing the science book.

I tell the kids that, even in a childhood marked by despair and deprivation, I knew that no matter what happened, I still had my family, or at least the remnants of a family ripped apart by divorce and then glued back together in various odd arrangements through a series of ill- advised remarriages. It was good to know I had a solid foundation.

Yes, U.S. travelers dress better. The British are always so conspicuous in hot climates. They don't seem to wear shorts. American men seem to be comfortable wearing hot-weather clothing.

Four times I was honked at for having the temerity to proceed through town without the benefit of metal.