This is a chapter in <i>The Undercover Economist</i>, a book that I just finished reading last week: <a href="http://www.amazon.com/Undercover-Economist-Exposing-Poor-Decent/dp/0195189779/" rel="nofollow">http://www.amazon.com/Undercover-Economist-Exposing-Poor-Dec...</a><p>It's a great introductory economics book for the layman.