Another benefit would be identifying patterns of illegal discrimination against women or minorities. Lilly Ledbetter, for whom the 2009 fair pay law is named, would have learned a lot sooner that she was making less than her male colleagues at a Goodyear plant in Alabama if she could have looked up their annual incomes on a government website.

Transparency could even help to increase economic growth. People who know how much their co-workers are paid — and how much people are paid at other companies, and in other industries — can make better career decisions.

Tax data also is a rich source of information about American life. The I.R.S. tightly limits access, but one of the few researchers allowed to work with that data, the Harvard economist Raj Chetty, has produced a series of important studies illuminating the mechanics of economic inequality. He and his collaborators have shown that Americans have a dwindling chance of making more money than their parents, and that living in a good neighborhood as a child has a lifelong impact on earnings. One can only imagine what others might learn from the data.

Calling for more disclosure may seem discordant at a time of growing concern about privacy. But income taxation is an act of government, not an aspect of private life. Property tax records provide a reasonable model . Local governments disclose the name of the property owner, the value of the property and the amount of taxes owed and paid. The same information should be available for income taxes — nothing more is necessary.

Another reasonable rule: In Norway, it is a matter of public record when someone looks at tax records. Everyone can see who is nosing around. Wisconsin, which makes income and tax information available on request, imposes the same requirement.

Income taxation in the United States began in public view. When Congress imposed the first income tax in 1861, during the Civil War, it required the disclosure of names, incomes and tax payments. Over the following decade, before Congress ended the tax, this data was posted in public and printed in newspapers.

That practice was briefly revived in 1924. It’s time for another revival. The question is whether Americans are willing to endure a little sunlight in the interest of fairness and equality.