The question of what an ideally just society looks like has been one of the perennial philosophical questions. In recent decades, it has essentially dominated the field of analytic political philosophy. Charles W. Mills, a distinguished philosopher who passed away on 20 September 2021, believed that was a mistake. An exclusive focus on the conditions of ideal justice meant ignoring the injustices of the real world, treating them as incidental rather than structural in nature. In exposing the ways in which ideology, oppression and racism can be systematic barriers to achieving the goal of justice, Mills cemented injustice as a philosophical problem worthy of study as much as any, writes Jason Stanley.