Book excerpt: This fifth volume in the book series on Nuclear Non-Proliferation in International Law focuses on various legal aspects regarding nuclear security and nuclear deterrence. The series on Nuclear Non-Proliferation in International Law provides scholarly research articles with critical commentaries on relevant treaty law, best practice and legal developments, thus offering an academic analysis and information on practical legal and diplomatic developments both globally and regionally. It sets a basis for further constructive discourse at both national and international levels. Jonathan L. Black-Branch is Dean of Law and Professor of International and Comparative Law at the University of Manitoba in Canada; a Bencher of the Law Society of Manitoba; JP and Barrister (England & Wales); Barrister & Solicitor (Manitoba); and Chair of the International Law Association (ILA) Committee on Nuclear Weapons, Non-Proliferation & Contemporary International Law. Dieter Fleck is Former Director International Agreements & Policy, Federal Ministry of Defence, Germany; Member of the Advisory Board of the Amsterdam Center for International Law (ACIL); and Rapporteur of the International Law Association (ILA) Committee on Nuclear Weapons, Non-Proliferation & Contemporary International Law.