Correctly understanding how technology affects finance and business is vitally important for the welfare and prosperity of ­nations. And for nearly two decades, it may have been the most important part of Alan Greenspan's job.

The departing chairman of the Federal Reserve Board of Governors is, of course, popularly linked with the "new economy" of the late 1990s -- and with its awful consequence, the "tech ­bubble." But as Roger Lowenstein, author of Origins of the Crash, explains in "How the Fed Learned to Love Technology" on page 78, the reign of the Fed chief, who will retire in January, coincided with a period of unprecedented innovation in information technology. When Greenspan took office in 1987, the PC was, for most consumers and businesspeople, just making its way onto the desktop, and the Internet was the province of a few hard-core technologists. That quickly changed. As the country's top banker, Greenspan was responsible for understanding how technology was affecting the economy. He was forced to ask whether conventional economic rules were suddenly irrelevant. Specifically, he wondered, did technology allow productivity to grow faster than economists had previously thought -- and help curb the risk of inflation?