The inviolability of diplomatic personnel and premises is a cornerstone of interstate relations and international law. As epitomized by the murder of US Ambassador Christopher Stevens in Benghazi, host countries are not always willing or capable to protect foreign diplomats and missions, which have become increasingly vulnerable to terrorism and other forms of political violence. Consequently, states with a large diplomatic presence have complemented host countries protection with a host of additional measures ranging from relocating embassies to fortified suburban locations to the deployment of military, police, and private security guards. By increasing the separateness of foreign envoys from local societies and informing local societies’ perceptions of the sending states, however, diplomatic security policies may not simply protect diplomats, but also reshape the institution and practice of diplomacy. In spite of its theoretical and policy relevance, diplomatic security has received very sporadic scholarly attention. This volume fills this gap by providing a comparative analysis of diplomatic protective policies enacted by the US, China, the UK, France, Germany, Italy, Russia, Israel and Turkey. Moreover, the book investigates the reasons underlying the evolution of diplomatic security policies over time and their variations across countries, examining the factors underlying the choosing of protective actors and arrangements. It then examines the effectiveness of these arrangements analyzing how diplomatic security policies have been reformed in response to major incidents and the extent to which they can secure diplomats without hindering their ability to interact with local society and tarnishing the image of the sending state.