Alan Krueger, the Princeton professor and economic adviser to two presidents who died last weekend, rang the alarm bell for me as a reporter six years ago with a disturbing speech that he gave, of all places, at Cleveland’s Rock and Roll Museum.

Krueger was one of those rare economists who break out of the ivory tower and plunge restlessly into the real world where the rest of us live and unearth vital and provocative insights into such disparate topics as rock and roll, the minimum wage, the opioid epidemic or what Krueger called “mind boggling” economic inequality.

In Cleveland,  Krueger let loose a thunderclap of empirical data to show that an astounding 84% of the entire nation’s growth in income from 1979 to 2011 went to the top 1 percent of families, and from 2000 to 2007 more than 100% of the growth in national income went to the top 1 percent.

His stark numbers stopped me cold. Until then, I had figured Occupy Wall Street’s chant about “the 99 percent vs 1 percent” was a catchy slogan that exaggerated reality. But Krueger’s figures proved that Occupy was right on. With hard data, Krueger documented that, in fact, the U.S. has not just an economic divide but a yawning canyon cleaving the super-rich from everyone else. And the canyon keeps getting wider and deeper.