John A. Vasquez explains the processes that cause the spread of interstate war by looking at how contagion worked to bring countries into the First World War. Analysing all the key states that declared war, the book is comprised of three parts. Part I lays out six models of contagion: alliances, contiguity, territorial rivalry, opportunity, 'brute force' and economic dependence. Part II then analyses in detail the decision making of every state that entered the war from Austria-Hungary in 1914 to the United States and Greece in 1917. Part III has two chapters - the first considers the neutral countries, and the second concludes the book with an overarching theoretical analysis, including major lessons of the war and new hypotheses about contagion. This book will be of great interest to students and scholars of international relations, conflict studies and international history, especially those interested in the spread of conflict, or the First World War.

‘Some scholars like to look at forests from the outside-in and never get too close to the trees. Others like to plunge into the forest and tag every tree. Despite the old adage of not seeing the forest for the trees, both approaches can prove profitable. John A. Vasquez's latest book is a tree-tagging exercise that pays off in generating an inside-out look at why war participation spreads. There is still more to learn about these contagious processes but tackling first one of the toughest nuts to crack in the war inventory, World War I, should make it easier to figure out why wars spread in general. And just when you thought everything had been said about World War I that could be said, Vasquez comes up with some new twists on how things worked between 1914 and 1918.'

William R. Thompson - Distinguished and Rogers Professor Emeritus, Indiana University

‘Contagion and War is a nuanced and systematic exploration of the multiple causal processes through which war might spread, illustrated by a detailed examination of the First World War. Vasquez makes a significant contribution to both the theory of international conflict and to our historical understanding of one of the world's most catastrophic and consequential wars.'

Jack S. Levy - Rutgers University, New Jersey

‘Contagion and War adds to our knowledge of World War I and multiparty conflicts … by recognizing that temporal sequences are involved in both the start and spread of belligerency, and teasing out and exploring the mechanisms associated with them.’

Richard Ned Lebow Source: War in History