Along with their considerable academic and real-world international water policy experience, this father-son team bring a lens of economics and international relations to their study of conflict and cooperation in international river basins under conditions of scarcity and variability. A good bit of the first half of the book builds from their earlier large-N analysis of treaties describing the relationship between scarcity and cooperation as an inverted U-shape where the level of institutionalized cooperation is low when the level of water scarcity is very low or very high. The greatest contribution can be found perhaps in the second half of the book where they investigate the mechanisms negotiated as part of these institutions to mitigate conflict and promote cooperation in the face of scarcity or variability, including information sharing, benefit sharing, issue linkage and side payments. The case studies exploring these mechanisms in practice are rich and diverse. They argue these mechanisms are a way to reach agreement in treaty negotiations but also be used as tools for continued cooperation. In this way, Dinar and Dinar move us from merely a study of treaty negotiation and design to one of treaty effectiveness and change. Taken together, their empirical analysis and case evidence demonstrate that existing, and future levels of scarcity and variability, can be accommodated by institutions and the mechanisms negotiated as part of these institutions. Treaty design matters but alas, there is no single mechanism or one-size-fits-all approach. This is important lesson for water practitioners designing and implementing treaties, but is equally compelling for water scholars keen to better understand what stimulates conflict and cooperation in shared river basins.