Ronald Reagan has left office and the fate of the Strategic Defense Initiative (SDI) is still undecided. This book provides an essential basis for evaluating the policy choices that the new U.S. leaders will face with respect to SDI through the 1990s. It explores key security and policy issues related to SDI including the emergence of SDI, technical evolution of the program since 1983, R & D in the 1990s, Soviet responses to SDI, issues for the allies, the effect of SDI on offensive and defensive nuclear strategies, options for arms control and the relationship between SDI and the overall U.S. defense posture. Contents: The Future of SDI: An Introduction, William J. Perry, Brent Scowcroft, Joseph S. Nye, Jr., and James A. Schear; SDI During the Reagan Years, Strobe Talbott; Trends in Strategic Defense Technologies, Thomas H. Johnson; The Near-Term Impact of SDI on Soviet Strategic Programs: An Institutional Perspective, Stephen M. Meyer; SDI and the All Jeffrey Boutwell; SDI and the Existing Arms Control Regime, Edward L. Warner III; The Structure of Future Agreements on Ballistic Missile Defense, Ashton B. Carter; SDI and the U.S. Defense Posture, Michael M. May; Appendix A: The 1972 ABM Treaty.