How does the expansion of real economic activity in the United States since 1991 compare with its historical precedents in terms of length, strength, composition, and sources? Was it really unique, marking the onset of a new age of both higher and more stable growth with no significant inflation? How justified are the expectations of strong and lasting productivity-enhancing innovations? These and many related questions are prompted by what is widely viewed as a surprising combination of economic and financial, domestic and foreign events at the end of the millennium. The essay is addressed to answering several of them.