Intelligence services are held to high expectations. Security has become a central societal value not only since the recent terrorist attacks. At the same time, intelligence services are required to strictly observe the individual rights and freedoms guaranteed by the constitution. The legal foundations of intelligence services have the task of ensuring both freedom and security. The Handbook of Intelligence Law offers, for the first time, a comprehensive and systematic treatment of the law applicable to intelligence services. Challenging national, European, and international legal questions are explored in a problem-oriented manner, taking into account real developments (e.g., proliferation, terrorism, economic espionage, or cyberattacks). The current scientific discourse as well as the present legal practice, including...