Interview with Peter Zimmerman, Emeritus Professor of Science and Security in the War Studies Department, King’s College London. Zimmerman recounts his upbringing in Wisconsin and then New Mexico in support of his father’s work in civilian and military defense, and he describes his early interests in science. He discusses his undergraduate experience at Stanford and the influence of Walter Meyerhof, and his decision to remain at Stanford for graduate school. Zimmerman discusses his postdoctoral appointments at DESY and then Fermilab until his first faculty appointment at LSU. He explains his involvement with the nuclear issues at the federal level in the 1970s and his offer to join the ACDA. Zimmerman discusses his opposition to strategic missile defense and he explains how his policy analysis work at the Carnegie Endowment filtered its way into policymaking. He describes the debates around ending nuclear testing and his interest in looking at nuclear weapons in the context of international terrorism. Zimmerman explains the negative security ramifications of the ACDA being folded into the Department of State and he explains his move to become Chief Scientist of Senate Foreign Relations Committee. He describes the scene in Washington on 9/11 and the subsequent anthrax attacks in Congress, and he explains why he never believed that Saddam Hussein had a WMD capability before the Iraq War. Zimmerman discusses his professorship in London and his opportunity to create a new center on science and security, and he shares his perspective on the JCPOA and what bothered him the most about Trump’s foreign policy decisions. At the end of the interview, Zimmerman reflects on how to best translate scientific analysis into good policy outcomes, and why a lack of public interest or media coverage should never make us lose sight of ongoing security threats.