Take air quality in the United States today: It's about 30 percent better than it was 25 years ago, even though there are now more people driving more cars.

Lest those islands still seem to you too remote in space and time to be relevant to our modern societies, just think about the risks... of our increasing globalization and increasing worldwide economic interdependence.

All human societies go through fads in which they temporarily either adopt practices of little use or else abandon practices of considerable use.

African cavalry mounted on rhinos or hippos would have made mincemeat of European cavalry mounted on horses. But it couldnt happen.

I'd rather spend my leisure time doing what some people call my work and I call my fun.

I've always been interested in a lot of things, and a lot of things at the same time, and I always tried to explain them to myself. I ask a lot of questions.

What did the last Easter Islander say as he chopped down the last tree? The Easter Islanders didnt have anthropologists.