Back in 1989, when the words "global warming" were only just beginning to enter the vernacular, Bill McKibben was way ahead of the curve. His book The End of Nature has since become a classic on the environment, but back then it was a revelation, laying out the science and implications of global warming and telling a great story to boot. Since then, McKibben has written seven more books, including Hope, Human and Wild, about local environmental success stories; Maybe One: A Case for Smaller Families, about population growth and the decision to have only one child; and "Long Distance," about a year spent training for long-distance cross-country ski racing. (He's also written books about genetic engineering and how to make Christmas more meaningful and less consumer-driven.)

A fascinating internal debate is whirling within the green community: Are the environmental tradeoffs worth the clean-energy benefits of wind power? The scuffle hinges on a massive