This book examines income inequality and income distribution by focusing on the compilation of economic concepts, statistical and econometrics techniques developed and used in the measurement and empirical analysis of inequality at different levels. In particular, a number of issues crucial to the studies of global income inequality are addressed. These are the concepts, measurements and decomposition of inequality throughout the world's distribution of income. Inequality is measured at different levels such as at the global, continental, international, intra-national and regional levels. Experiences gained from the analysis on these issues are then reflected in a discussion of the data and their role in the generation of the disparity and direction of changes in global income inequality. This book represents new developments in various decomposition of income and poverty measurements to illustrate methods, their usefulness and empirical results. In the evaluation of diverse methodologies, their strength and weaknesses are highlighted.