Book excerpt: The Oxford Handbook of National Security Intelligence is a state-of-the-art work on intelligence and national security. Edited by Loch Johnson, one of the world's leading authorities on the subject, the handbook examines the topic in full, beginning with an examination of the major theories of intelligence. It then shifts its focus to how intelligence agencies operate, how they collect information from around the world, the problems that come with transforming "raw" information into credible analysis, and the difficulties in disseminating intelligence to policymakers. It also considers the balance between secrecy and public accountability, and the ethical dilemmas that covert and counterintelligence operations routinely present to intelligence agencies. Throughout, contributors factor in broader historical and political contexts that are integral to understanding how intelligence agencies function in our information-dominated age.