"Regina Hagen, who grew up in Germany during the Cold War, became actively involved in the campaign to abolish nuclear weapons after hearing an inspirational speech by Joseph Rotblat, founder of the Pugwash movement for global nuclear disarmament and Nobel Peace Prize laureate. Hagen became a coordinator of INESAP, the International Network of Engineers and Scientists Against Proliferation, which she describes as an interface between the political, scientific and activist arenas. She is now the managing editor of the quarterly magazine ""Wissenschaft und Frieden"" (Peace and Science).

Hagen attended the May 2012 NPT Preparatory Committee with a group of German university students learning about nuclear disarmament and the work of the UN. While in Vienna, she took time out to discuss a variety of topics including young people, the importance of the CTBT and the challenges to its entry into force.

Disclaimer: The views expressed in this interview do not necessarily reflect the positions of the CTBTO."

Nuclear physicist Patricia Lewis has headed some of the world's most prestigious think-tanks and institutions dealing with arms-control, disarmament and international verification.From 1997-2008, Lewis was Director of the UN Institute for Disarmament Research (UNIDIR) in Geneva. Earlier in her career, she was Executive Director at the Verification Research, Training and Information Centre (VERTIC) in London. Before taking up her current post at Chatham House, Lewis spent more than three years as Deputy-Director and Scientist-in-Residence of the James Martin Center for Nonproliferation Studies in Monterey, California. --- In a broad-ranging interview conducted in Vienna during the May 2012 Preparatory Committee for the Nuclear Non-Proliferation Treaty Review Conference, Lewis reflected on her career to date, challenges for the future, and her hopes for a nuclear weapons-free world.Disclaimer: The views expressed in this interview do not necessarily reflect the positions of the CTBTO.

Siegfried Hecker, former Director of Los Alamos National Laboratory from 1986 through 1997, is a nuclear weapons expert specialising in materials science and one of the world's leading experts on plutonium science. His role was crucial for the maintenance of the U.S. nuclear arsenal without explosive testing. Hecker has visited North Korea several times at the invitation of the government and witnessed first-hand the country's nuclear programme development. In addition, since the end of the Cold War, he has worked on fostering collaboration between Russian and American nuclear scientists. He is now Co-Director of the Center for International Security and Cooperation at Stanford University.Hecker talked to CTBTO Faces in September 2011 while in Vienna to lecture at the CTBT Introductory Course.Disclaimer: The views expressed in this interview do not necessarily reflect the positions of the CTBTO.

Joe Cirincione, whose commentaries are featured in media worldwide, has been an influential voice in nuclear arms-related issues for many years. He is a member of Secretary of State Hillary Clinton's International Security Advisory Board and of the Council on Foreign Relations. As Director for Nonproliferation at the Carnegie Endowment for International Peace, he organized and chaired the annual Carnegie International Non-Proliferation Conferences for five years. Since 2008, Cirincione serves as President of the Ploughshares Fund, a public grant-making foundation active in nuclear arms control and conflict resolution. He also teaches at the Graduate School of Foreign Service at Georgetown University.Speaking on the margins of the July 2012 CTBTO Intensive Policy course , where he was the keynote speaker, Cirincione recalled the 'duck and cover' drills of his childhood and discussed issues such as the implementation of President Obama's nuclear policy and the chances of U.S. ratification of the CTBT after the upcoming presidential elections. Disclaimer: The views expressed in this interview do not necessarily reflect the positions of the CTBTO.