Paul Krugman speaks at the World Affairs Council of Northern California.One of the world's preeminent economists and an insightful, outspoken commentator on economic and political affairs, Paul Krugman will give a preview of his upcoming book, The Conscience of a Liberal. In it, Professor Krugman evaluates American social policy and leadership over the last century, and considers where we go from here, as we enter the 21st Century.