This book describes friendship as a social bond in the aristocratic society of the French seventeenth century, the "Grand Siècle", with a particular emphasis on the milieu of the court and the role of friendship in its political dynamics. Based on letters and memoirs of the period, it examines the different dimensions of the phenomenon. Besides the semantics of the words "ami" and "amitié", the representations of friendship are analyzed. The language of friendship, its vocabulary and rhetoric are also described. The practices of friendship, its rituals and gestures are examined, as well as the objects that could become symbols of friendship, and the services among friends, notably in the fields of politics, of mutual material help and of assistance in armed conflicts. The results of this analysis are embedded in a "longue durée" perspective, which outlines the evolution of friendship and the changes between the early modern and the modern age. The study's results show that it is necessary to historicize the concept of friendship itself in order to understand early modern friendship.