The U.S. economic expansion is now in its tenth year, showing no signs of slowing down. The rate of labor productivity growth has doubled in recent years, instead of falling as the expansion matured as in previous postwar expansions. Moreover, core inflation remains low despite record employment and the lowest jobless rates in a generation. Our sustained economic strength with low inflation suggests that the U.S. economy may well have crossed into a new era of greater economic prosperity and possibility, much as it did after the development and spread of the electric dynamo and the internal combustion engine.