This volume includes a representative selection of Sidney Drell's recent writings and speeches (circa 1993 to the present) on public policy issues with substantial scientific components. Most of the writings deal with national security, nuclear weapons, and arms control and reflect the author's personal involvement in such issues dating back to 1960.Fifteen years after the demise of the Soviet Union, the gravest danger presented by nuclear weapons is the spread of advanced technology that may result in the proliferation of nuclear weapons. Of most concern would be their acquisition by hostile governments and terrorists who are unconstrained by accepted norms of civilized behavior. The current challenges are to prevent this from happening and, at the same time, to pursue aggressively the opportunity to escape from an outdated nuclear deterrence trap.Contents:My Involvement as a Scientist Working on Issues of National Security and Views on Scientists' Responsibilities and Ethical DilemmasIssues Coming to the Fore Immediately Following the Collapse of the Soviet Union and the End of the Cold WarAt the End of the 20th Century: The Comprehensive Test Ban Treaty and the Emergency of the New Terror of Biological and Chemical WeaponsNew Challenges in the 21st Century: Escaping the Nuclear Deterrence Trap and Facing TerrorismMemorials to Four Colleagues Who were Great Scientists and CitizensAfterword: What are Nuclear Weapons for?Readership: Students, academics and professionals in the fields of national security, international relations; researchers and policy-makers in nuclear policy think tanks.