RAND National Security Publications
RAND's work involves most of the major disciplines in the physical, social, and biological sciences, with emphasis on their applications to problems of policy and planning in domestic and foreign affairs. All of RAND's unclassified work since 1998 is available online free of charge. Reports from before 1998 are gradually being scanned in, and released as free electronic editions; these reports are also available for purchase.
Some national security research is also published by other presses.