Earlier this year, a banking crisis led to three major bank failures, and the turmoil it caused continues to haunt U.S. markets, adding more fuel to fears of a recession. Few people saw it coming. The same was true in 2008. There were certainly some analysts and investors who had become alarmed by the blinking red lights prior to the crash: the warning signs of a credit and housing bubble. But Alan Greenspan, who served as chair of the U.S. Federal Reserve for decades, admits that he was not one of them.

In a 2013 postmortem, Greenspan details the blunders and false assumptions that led to the 2008 financial collapse. When he wrote the essay, the financial crisis was largely in the rearview mirror, but economists and policymakers were still trying to piece together what had gone so wrong.

As the former Fed chair, a position he held for an unprecedented five terms from 1987 to 2006, Greenspan was a key decision-maker in the years leading up to the crisis—and he failed, with many other experts, to predict major risks that would lead to financial collapse. “What went wrong? Why was virtually every economist and policymaker of note so blind to the coming calamity?” Greenspan wrote. “How did so many experts, including me, fail to see it approaching?”