The profound impact of economic inequality on individuals and societies cannot be overstated. On one hand, rewarding talent, effort, and creativity drives economic growth and technological progress. On the other hand, economic inequality grants material advantages to some while denying them to others. Against this backdrop, this chapter introduces two critical challenges related to economic inequality. First, there is no consensus on what constitutes a morally “tolerable” economic inequality. Inequality resulting from an uneven playing field, segregation, or discrimination is seen as inherently intolerable. While some inequalities may not meet this threshold, that doesn’t mean they are automatically acceptable. The concept of tolerable inequality remains deliberately undefined, reflecting the complex and contested nature of what society deems fair. Second, even inequality that might be deemed tolerable can inherently contain the seeds of future, intolerable inequality. Together, these challenges cast serious doubt on the manageability of economic inequality and may help explain its vast variation across time and space.