Adam Tooze, a history professor at Columbia University, is the author of "Shutdown--How Covid Shook the World's Economy." Never before did the global economy contract by 20 percent in a matter of weeks as it did in 2020. While the number of people contracting covid as well as the heated debate over mask use and opening of facilities is finally easing, it's important to understand the impact of the worldwide pandemic. Tooze's article in the New York Times article referenced in the discussion was published in the Sept. 1, 2021 edition.