The military, political, and economic preeminence of the United States during the post-World War II era is based to a substantial degree on its superior rate of achievement in science and technology, as well as on its capacity to translate these achievements into products and processes that contribute to economic prosperity and the national defense. The success of the U.S. scientific enterprise has been facilitated by many factors, important among them the opportunity for American scientists and engineers to pursue their research-and to communicate with each other-in a free and open environment. During the last two administrations, however, concern has arisen that the characteristically open U.S. scientific community has served as one of the channels through which critical information and know-how are flowing to the Soviet Union and to other potential adversary countries; openness in science is thus perceived to present short-term national security risks in addition to its longer-term national security benefits in improved U.S. military technology. The Panel on Scientific Communication and National Security was asked to examine the various aspects of the application of controls to scientific communication and to suggest how to balance competing national objectives so as to best serve the general welfare. The Panel held three two-day meetings in Washington at which it was briefed by representatives of the departments of Defense, State, and Commerce, and by representatives of the intelligence community, including the Central Intelligence Agency, the Federal Bureau of Investigation, the Defense Intelligence Agency, and the National Security Agency. The Panel also heard presentations by members of the research community and by university representatives. In addition to these briefings, the Rand Corporation prepared an independent analysis of the transfer of sensitive technology from the United States to the Soviet Union. To determine the views of scientists and administrators at major research universities, the Panel asked a group of faculty members and administrative officials at Cornell University to prepare a paper incorporating their own views and those of counterparts at other universities. The main thrust of the Panel's findings is completely reflected in this document. However, the Panel has also produced a classified version of the subpanel report based on the secret intelligence information it was given; this statement is available at the Academy to those with the appropriate security clearance.