Excellent Planet Money podcast on the same topic: http://www.npr.org/sections/money/2014/04/25/306862378/episode-534-the-history-of-light http://www.npr.org/sec

Excellent Planet Money podcast on the same topic: http://www.npr.org/sections/money/2014/04/25/306862378/episode-534-the-history-of-light http://www.npr.org/sections/money/2014/04/25/306862378/episo... Basically, the history of light makes for a nice capsule summary of the entire history of our economic development.