The single most important source of financial support for public education today is the local property tax. It accounted for an estimated 52 percent of all revenues received by U. S. public schools in the 1970–71 school year. Despite this fact, the property tax is increasingly under attack. Local school districts are asked to finance the increasing demands placed on their school systems from a tax whose base is sharply eroded by exemptions. To make matters worse, the property tax may be inelastic with respect to income. That is, the rate of increase in market value of taxable property may be less than the rate of increase in income. In addition, some opponents claim that the property tax is regressive; that is, it places a greater burden on the poor than on the rich because the poor pay a greater proportion of their income in property taxes. They argue that real property is not a completely reliable indicator of wealth or ability to pay. The property tax is thus unacceptable to those who believe that schools should be financed by those best able to pay. In addition, the property tax is unacceptable to those who believe that schools should be financed by those who receive the benefits. However, since society in general benefits from education, allocation of benefits and costs is a difficult task.