National security intelligence is a vast, complicated, and important topic, made doubly hard for citizens to understand because of the thick veils of secrecy that surround it. This definitive introduction to the field guides readers skilfully through this hidden side of government. It not only explains the three primary missions of intelligence - information collection and analysis, counterintelligence, and covert action - it also explores the wider dilemmas posed by the existence of secret government organizations in 'open' societies. With over thirty-five years of experience studying intelligence agencies and their activities, Loch Johnson illuminates difficult questions such as why intelligence organizations make mistakes in assessing world events; why some intelligence officers decide to work against their own country on behalf of foreign regimes; and how agencies succumb to scandals, including spying on the very citizens they are meant to protect.National Security Intelligence is tailor-made to meet the interests of students and general readers who care about how nations protect themselves against threats through the establishment of intelligence organizations - and how they continue to strive for safeguards to prevent the misuse of this secret power.