In occasion of the 70 years of the Atlantic Alliance, the purpose of the thesis is to answer the question: is NATO "brain-dead" - as the French President Emmanuel Macron declared - or is it rather shapeshifting once again in order to adapt to a rapidly changing international scenario? To the end of assessing whether or not NATO will be able to maintain its role as the guarantor of peace and overall well-being in the Euro-Atlantic area, the book retraces the history of the Alliance and in particular that of the crises that affected it in order to downsize the current perception of constant threat and even decay.