Jeffrey Sachs: A Dangerous Cliff is Metaphor for USbr National Constitution Center - The National Constitution Centerbr For Earth Day, 2008 the National Constitution Center welcomes Jeffrey Sachs, one of the world's greatest economic minds and author of The New York Times bestseller 'The End of Poverty', for a discussion about the global economic system and his new book br 'Common Wealth: Economics for a Crowded Planet.