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.