Power laws are pervasive in economics and social sciences, particularly in the upper tails of distributions such as wealth, income, frm size, and city populations. Their scale-free property makes them a universal framework to understand phenomena spanning several orders of magnitude. This chapter explores their mathematical and ofen counterintuitive statistical properties, empirical evidence, and the stochastic processes that generate them. Emphasis is placed on their universal applicability, particularly to frm size, wealth, and income distributions and their potential to address the pressing issues of our time.