[Excerpt] This report presents recent analysis of the distribution of income and the extent of income mobility in the United States over time and in comparison with other advanced economies. It begins with a discussion of data issues related to measuring income and its distribution. The empirical literature on the development of and explanations for income inequality in the United States are next addressed. The report then compares the U.S. income distribution with the distributions of other industrialized countries and presents explanations for cross-country differences in equality measures. To the degree that a more equal distribution of income arises from policy decisions rather than market forces, the willingness of a country to incur any economic costs related to attaining greater equality may reflect varying national beliefs about the opportunity to ascend the income ladder. For that reason, the report closes with an examination of income mobility in the United States and other developed nations.