Some might say climate change is the critical global issue so it must be clean energy. Others might say nothing will make as much difference for the world's people as educating and empowering girls and women. Closer to home, a case can be made that public financing of political campaigns would have the most impact on all such issues by making it possible for the power of the United States to become a greater force for good.

All good answers, but this week's guest gives another answer - and its one that I share. Frances Moore Lappe, who has herself been a force for good at least since the publication of the phenomenal best-seller Diet for a Small Planet in 1971, says that the greatest impact would follow from changing our minds.

In her 18th book, ECOMIND: CHANGING THE WAY WE THINK, TO CREATE THE WORLD WE WANT, Lapp� argues that much of what is wrong with the world, from eroding soil to  eroding democracies, results from ways of thinking that are out of sync with human nature and nature's rhythms. Humans are doers, she says. But our capacity for doing is undermined by seven "thought traps" that leave us mired in fear, guilt, and despair -- none of which are motivators to action.

Drawing on the latest research in climate studies, anthropology, and neuroscience, she weaves her analysis together with stories of real people the world over, who, having shifted some basic thought patterns, now shift the balance of power in our world. Chapter-by-chapter, Lapp� takes us from "thought trap" to "thought leap," and with each shift, challenges become opportunities.