Taking advantage of recent advances in game theory and the latest historiography, Frank C. Zagare offers a new, provocative interpretation of the events that led to the outbreak of World War I. He analyzes key events from Bismarck's surprising decision in 1879 to enter into a strategic alliance with Austria-Hungary to the escalation that culminated in a full-scale global war. Zagare concludes that, while the war was most certainly unintended, it was in no sense accidental or inevitable. The Games of July serves not only as an analytical narrative but also as a work of theoretical assessment. Standard realist and liberal explanations of the Great War are evaluated along with a collection of game-theoretic models known as perfect deterrence theory.