The story of Evelina Jenkins, a black South Carolina Sea Islands native, offers a case in point. She owned dozens of acres of property — including an entire island — at a time in the early 1970s when land values along the state’s coastline were skyrocketing. As a result of the state’s pitiful expenditures on “colored” schools, Ms. Jenkins had received only minimal education and never learned to read. Decades of disfranchisement and white control of local government and the courts had taught her that whatever rights and protections it afforded did not apply to her. Even venturing inside the local government offices where people registered for licenses or paid their taxes was an invitation to be mistreated and humiliated, and was something to avoid.

So Ms. Jenkins entrusted a white neighbor who had befriended her to take her annual property tax payments to town for her. But rather than submitting Ms. Jenkins’s payments, he pocketed them, then waited for her taxes to fall delinquent, whereupon he bought the lien to her property at the county’s annual tax auction. Then, after the statutory redemption window closed, he gained title to her landholdings, island and all, which he subsequently resold to a developer. In the decades since, the land Jenkins once owned has generated untold amounts of wealth. Houses on the island she once owned today sell for upward of $400,000. Ms. Jenkins, though, never saw a dime of it. Rather than leave her children an ample inheritance, she died penniless, forced to live out her last days in her daughter’s mobile home.

While Ms. Jenkins’s case was particularly egregious, the legal theft of black land in similar ways was not uncommon. In booming real estate markets like Hilton Head and surrounding Sea Islands, tax sales afforded investors a lucrative opportunity to acquire valuable property for pennies on the dollar. Here and elsewhere, local tax assessors served as accessories before the fact, deliberately overvaluing black-owned land or enacting sharp, capricious assessment spikes as development crept near, all aimed at forcing poor black farming families to sell under duress or steering them into tax delinquency.

Tax sales were just one of several ways speculators and developers manipulated property and tax laws, and exploited historic inequities, to expropriate black people’s land. Another was the forced partition sale. Because whites controlled the courts, blacks who acquired property during Jim Crow often opted to handle matters of inheritance informally, outside of the legal system. Instead of probating their wills, black property owners tended to bequeath their property to descendants in the form of undivided shares — an arrangement under which heirs become co-owners of a property, each with the right to sell his or her own interest. Predatory land speculators would search for a person who had recently inherited land this way and was willing to sell his or her share. Once the sale went through, the speculator — now a co-owner of the property — would have the right to petition the courts to order a sale of the entire tract of land (against the wishes of those family members who lived on it) and would then buy it.

These partition sales invariably resulted in the land being sold at well below its market value, enriching the buyer while leaving the displaced and dispossessed family members with nothing. Speculators have used this legal trick to force the sale of millions of acres of black-owned land over the past several decades. Only in the past couple of years have some states begun to adopt a uniform law designed to curb the most predatory abuses of heirs property laws. Much of the damage, though, has been done.

Indeed, many of the techniques used to take black-owned land remain legal today. The tax-sale law that allowed someone to steal Ms. Jenkins’s land remains on the books in South Carolina and many other states, and continues to be used to extract wealth from poor and vulnerable communities across America. Tax buying thrived in the wake of the 2008 housing foreclosure crisis, as the number of tax-delinquent homes mushroomed, and today in gentrifying cities, where rising property assessments function as a self-fulfilling prophecy, predicting the changes local officials hope to bring and forcing low-income people out.

Many local governments have resisted calls to protect homeowners from predatory tax buying and have instead sought to increase profitability for investors; other cities have taken aggressive steps to foreclose on tax-delinquent properties. Between 2011 and 2015, Detroit initiated tax foreclosures on one out of every four properties in the city, an epidemic of tax delinquency caused, in large measure, by the illegal over-assessment of lower-valued properties. Then and now, the victims of discriminatory overtaxation and predatory tax buying are disproportionately black.