This volume collects the 16 invited lectures on macroeconomics delivered at the Twelfth World Congress of the International Economic Association in Buenos Aires, 23–27 August 1999. Responsibility for issuing the invitations and suggesting topics rested with me, so I am fully accountable for selection bias. Authors knew that they were addressing a general audience. They were urged to cover a broad topic rather than a sharp contribution, and to present their own views rather than a balanced survey. The typical lecture summarized, with a minimum of technicality, the main conclusions of the author’s research over a decade or more in some broad area of relevance to macroeconomics. Beyond the value of the individual lectures, this volume offers a selective but largely spread-out picture of ongoing research in macroeconomics. I first summarize the lectures (section 1.1), then offer some speculative conclusions of my own on the state of the discipline (section 1.2).