This chapter introduces the notation and basic concepts that are used throughout the book. The chapter has four five sections. First we reviews unidimensional poverty measurement with particular attention to the well-known Foster-Greer-Thorbecke measures of income poverty as many methods presented in Chapter 3 as well as the measure presented in Chapters 5-9 are based on these measures. The second section introduces the notation and basic concepts for multidimensional poverty measurement that will beare used in subsequent chapters. Third we define the issue of indicators’ scales of measurement, and fourth, address issues of comparability across people and dimensions. The fifth section systematically explains different properties that have been proposed in axiomatic approaches to multidimensional poverty measurement, which enable the analyst to understand the ethical principles embodied in a measure and to be aware of the direction of change they will exhibit under certain transformations.