Many debates in interstate conflict and peace research address an important yet complex question: how, and to what degree, are the behavior of states and their relationships among one another fundamentally changing? The period after 1945 has seen a significant decline in the degree and intensity of warfare among states. While civil wars remain common, numerous scholars argue that a "long peace" has taken hold in which militarized interstate violence has become less common. Some argue that war has become obsolete as cultural attitudes toward war have changed, while others emphasize cognitive shifts that have reduced overall levels of human violence. Others favor material factors that have altered the historical net benefit of warfare among states.

In Piecing Together the Peaces, Alexander K. Antony and William R. Thompson provide a novel explanation for how peace took hold in the international system and why state behavior drastically changed. According to the standard line of reasoning, states need only democratize, liberalize their trade, modernize their economic culture, or choose to forego territorial pursuits to reach peace with another state. As Antony and Thompson argue, most, if not all, of the processes put forward as causes of modern peace are highly intertwined with the macro-process of industrialization. Marshaling a long-view perspective, they show how the introduction of mechanization into production significantly altered nearly all aspects of economic and social life, including the costs and benefits of warfare. Rather than outlining a universal pathway through which states can arrive at peace, Antony and Thompson make the case that industrialization provides the starting point from which we can begin to unpack the transformation in conflict propensities among certain states. A bold challenge to the conventional wisdom that dominates interstate peace research, Piecing Together the Peaces shows that industrialization serves as the foundation for all other factors and processes fueling interstate peace.