Two main categories of social inequality are inequalities of condition and inequalities of opportunity. Inequalities of condition refer to differences in physical and material well-being: food, shelter, physical security, good health, and so on. Inequalities of opportunity are differences in chances of gaining power, respect, and well-being. The chapter discusses inequalities based on class, race, gender, age, and level of education—among others—that determine why some people and not others are able to get what they want out of life. Four things seem to limit people's opportunity to get what they want out of life: exclusion, disability, decoupling, and scarcity. Decoupling disconnects certain groups from rewards by keeping them uninformed about good opportunities and ways of taking advantage of them. Exclusion is the first way of controlling access to rewards and opportunities. At least three kinds of exclusion are worth examining at length: exclusion resulting from class structure, race, and professionalization.