IT is now nearly 20 years since Glazer and Moynihan began Beyond the Melting Pot, their classic study of ethnic groups in New York City. In it they wrote that “the ethnic groups... are also interest groups. This is perhaps the single most important fact about ethnic groups in New York City.” And in a situation in which “it has been common to speak about the ethnic groups in terms of either blame or praise...” it must be expected that “most people will simply have to use arguments and facts and ideas as weapons, and will not be able to use them for enlightenment.” This sad prediction has been proved correct by 20 years of academic and ethnic-group polemics, occasionally interrupted by a work such as American Ethnic Groups, edited by Thomas Sowell, professor of economics at UCLA and previously author of Race and Economics.