...argues that the Massachusetts property tax system discriminates against low income people and others who live in low income communities based on a survey of 253 cities and towns; states that people living in the lowest income communities pay triple the taxes of people living in the highest income communities and spend much less per pupil in school expenditures; appendices list communities with the highest tax rates, the highest and lowest median income, the highest and lowest amounts of taxable property per person, the highest density, the highest and lowest per pupil expenditures and the highest and lowest percentage of taxes spent on schools...