NATOs 2010 Strategic Concept officially broadened the allianceamp8217s mission beyond collective defense reflecting a peaceful Europe and changes in alliance activities. NATO had become an international security facilitator a crisismanager even outside Europe and a liberal democratic club as much as a mutualdefense organization. However Russiaamp8217s reentry into great power politics has changed NATOamp8217s strategic calculus.Russiaamp8217s aggressive annexation of Crimea in 2014 and its ongoing military support for Ukrainian separatists dramatically altered the strategic environment and called into question the liberal European security order. States bordering Russia many of which are now NATO members are worried and the alliance is divided over assessments of Russiaamp8217s behavior.amp160 Against the backdrop of Russiaamp8217s new assertiveness an international group of scholars examines a broad range of issues in the interest of not only explaining recent alliance developments but also making recommendations about critical choices confronting the NATO allies. While a renewed emphasis on collective defense is clearly a priority this volumeamp8217s contributors caution against an overcorrection which would leave the alliance too inwardly focused play into Russiaamp8217s hand and exacerbate regional fault lines always just below the surface at NATO. This volume places rapidfire events in theoretical perspective and will be useful to foreign policy students scholars and practitioners alike.