The global balance of power has been shifting throughout the past decade and, faced with a changing security landscape, more countries across the NATO alliance and around the world have been compelled to reassess their defense and security strategies. This book, NATO and the South: A Tale of Three Futures, presents a report based on a study conducted in the framework of a NATO SPS Multi-Year Project and designed to assess and explore key variables likely to impact the political environment of NATO's southern neighborhood over the coming years. The book reiterates the importance of a 'consistent, clear and coherent' approach to the South with the aim of ensuring that NATO remains ready, strong, and united for a new era of increased global competition. It outlines possible sources of change and introduces additional perspectives, exploring ways in which the Alliance can continue to adapt. Conflict spillover from fragile or failing states, instability and terrorism in the Sahel and Iraq, transnational terrorist groups such as Daesh and Al Qaeda and illegal trafficking of small arms and light weapons are all covered, as are the deteriorating security situation in the Sahel, the growing terrorist threat, and the instability of several countries in the area which constitute serious concerns for the alliance. The book and its recommendations provide a timely contribution to the reflection surrounding the development of the new NATO Strategic Concept in the context of preparations for the Madrid Summit, providing a useful basis to inform decision-makers from NATO member and partner countries.