The last book by Milanovic, lead economist of the World Bank research division is, as it says in its subtitle, "a brief and idiosyncratic history of global inequality." The book is structured around three main essays: one on within country inequality, another one on between countries inequality, and another on global citizen inequality. Each of these essays summarizes and gives a personal interpretation of the economic literature on these issues. After each main essay there are some shorter chapters, called vignettes, where the author illustrates the main topics with episodes from history or literature. There are two important ideas among others in this book. One is that inequality among countries (locational inequality) is today much larger than within-country inequality, as opposed to what happened until the ninetieth century. Overall, the place of birth and the income class of the parents determine 80% of anyone's income, the remaining 20% left to luck and effort. The other main idea is that there are important reasons to worry about global inequality, although there is no global political authority to whom we can send our complaints (perhaps we should build one). The reasons have to do with a practical and an ethical reason. The practical reason is that huge inequalities at the global level create political tensions, potentially chaos that may ignite huge migration movements. The ethical reason is that from a cosmopolitan criterion of social justice, there is no reason why we should worry more about citizens from our country than about human beings from other countries.