Introduction: An Alliance for the 21st Century John Andreas Olsen I. NATO’s Enduring Relevance Svein Efjestad and Rolf Tamnes II. Permanent Deterrence and US Military Presence in Europe Alexander R Vershbow and Philip M Breedlove III. NATO as a Partner Malcolm Chalmers IV. The Evolution of the Russian Threat to NATO Andrea Kendall-Taylor and Jeffrey Edmonds V. NATO’s China Challenge Janka Oertel VI. NATO and its Southern Flank Ziya Meral VII. NATO’s Maritime Domain Keith Blount and James Henry Bergeron VIII. Maintaining NATO’s Technological Edge Tim Sweijs and Frans Osinga IX. NATO’s Nuclear Posture and Arms Control Corentin Brustlein X. The Need for the Alliance to Adapt Further Heinrich Brauss