The era of Atlantic revolutions spanning the last decades of the 18th century opened the way towards the development of close ties between Europe and the USA. By turns object of curiosity, fascination, land of immigration and scene of merciless combats, the United States early impressed careful observers with their institutional organization, their massive size and their unlimited potential. From the intervention in the World War I, the relationship between the old and the new continent became ambivalent. So it continued following America’s intervention in World War II, and in the Cold War. Today, the existence of major tensions between a Europe in search of unity and the United States considered as - the policeman of the world remains visible. This volume is not meant to analyze these tensions but more to put them into perspective with a view to fostering a better understanding of the impact of the continual shift between cooperation, competition and even misunderstanding in a world where it is clearly important to keep an eye on your partner’s attitudes.