This essay offers a brief history of macroeconomics, together with an evaluation of what has been learned over the past several decades. It is based on the premise that the field has evolved through the efforts of two types of macroeconomist—those who understand the field as a type of engineering and those who would like it to be more of a science. While the early macroeconomists were engineers trying to solve practical problems, macroeconomists have more recently focused on developing analytic tools and establishing theoretical principles. These tools and principles, however, have been slow to find their way into applications. As the field of macroeconomics has evolved, one recurrent theme is the interaction—sometimes productive and sometimes not— between the scientists and the engineers.
