A former Harvard professor of decision science and game theory draws on those disciplines in this review of controversial strategic and tactical decisions of World War II. Allied leadership-although outstanding in many ways-sometimes botched what now is termed meta-decision making or deciding how to decide. Operation Jubilee, a single-division amphibious raid on Dieppe in August 1942, illustrates the pitfalls of groupthink. Prior to the invasion of North Africa in November, American and British leaders fell victim to the planning fallacy, going in with rosy expectations for easily achievable objectives. In the conquest of Sicily, they violated the millennia-old principle of command unity-now re-endorsed and elaborated on by modern theorists. Had Allied tacticians understood the game-theoretic significance of the terrain and conditions for success at Anzio, they might well not have and landed two-plus divisions there to fight a months-long stalemate in the first half of 1944.