Recently, there have been multiple high-profile incidents involving the release of classified government information. Perhaps most prominent was Wikileaks.org's unauthorised publication of more than 600,000 classified Department of Defense documents. Such incidents have further heightened congressional, media and public interest in classified information policy. This book provides information on classified information policy, also known as security classification policy and national security classification information policy. It discusses the history, costs and agencies assigned roles in classified information policy and focuses on Executive Order 13526, which establishes much of the current policy and possible oversight issues for Congress.