WASHINGTON — When Branko Milanovic, a World Bank economist, published “The Haves and the Have-Nots,” a study of global income inequality, last year, one of his most striking observations was the extent to which the subject was taboo in the United States.

As Mr. Milanovic explained, “I was once told by the head of a prestigious think tank in Washington, D.C., that the think tank’s board was very unlikely to fund any work that had income or wealth inequality in its title. Yes, they would finance anything to do with poverty alleviation, but inequality was an altogether different matter.”

“Why?” Mr. Milanovic asked. “Because ‘my’ concern with the poverty of some people actually projects me in a very nice, warm glow: I am ready to use my money to help them. Charity is a good thing; a lot of egos are boosted by it and many ethical points earned even when only tiny amounts are given to the poor. But inequality is different: Every mention of it raises in fact the issue of the appropriateness or legitimacy of my income.”

I recalled Mr. Milanovic’s remarks this week when I found myself on a panel at the Brookings Institution, one of those Washington research groups, discussing income inequality, including the research collected in a new book published by Brookings titled “Inequality in America.” In reply, Kemal Dervis, the vice president of Brookings, who co-wrote the book and led the panel, joked that if he turns up on the job market next month we will know he overstepped the mark.