Economics arranges its topics as Big, Medium, and Small. Mr Big is the Industrial Revolution: How did it happen, and when? Whence did it spread, and at what rate? What were the costs and benefits? The literature is vast and the answers are numerous. But it organizes around a fundamental phenomenon: from about 1800, economic growth began an upward climb that in fifty years captured the world's purse and that in another half century had increased the wealth of industrial nations many times. Intoxication with this achievement is expressed in museums of science and industry and on websites featuring the Paris Exhibition of 1889 and the Chicago Exhibition of 1893.