During the Second World War and the subsequent Cold War, foreign agents conducted intelligence-gathering, sabotage, and subversive operations inside neutral countries aimed at damaging their opponents’ interests. The essays contained in this collection analyze the risks of espionage operations on neutral soil as well as the dangers their covert activities posed for the governments of neutral states. In striving to avoid involvement in the firing line of the Second World War or the front line of the Cold War, the contributors argue that neutral states developed security policies that focused on protecting their own sovereignty without provoking overt hostility from any of the great powers. This collection describes how the warring parties engaged in competition on neutral territory and analyzes how neutral governments rose to the existential challenge posed by international spies, their own venal officials, and even foreign assassins.