In this interesting collection, expert analysts assess the costs of ten global problems over the past century, measured in economic terms, and make projections about their costs in 2050 (or 2100 in the case of climate change). The ten problems are air pollution, armed conflict, climate change, threats to ecosystems and biodiversity, inadequate education, gender inequality, illness, malnutrition, trade barriers, and poor water and sanitation. Putting aside armed conflict, the past century has been a good one, in the sense that the estimated costs of these various problems were much higher at the beginning of the century than at the end. The book’s contributors expect such improvements to continue until the middle of this century, although they project that the costs associated with climate change will rise sharply toward the end of the century. The estimates the book provides are certain to be challenged, but there is value in its attempt to quantify the effects of problems that are typically discussed only in qualitative and often emotional terms and in the way it shows how much progress has been made -- and how much further the world needs to go.