David Warsh, the author of "Knowledge and the Wealth of Nations" writes a weekly piece that is available for free on his web site [www.economicprincipals.com].  I have attached the most recent edition to this page for your pleasure.  He writes about both the importance of productivity and our quest for better understanding of its origin.  I have given you the conventional wisdom in class, but there remains much more to be learned.  From time to time I will include other Warsh essays for your reading.  Warsh was formerly the economics columnist for the Boston Globe and, I believe, has a Ph.D. in economics from Harvard.