Festschriften are collective essays presented to a scholar (more than often a University professor) by his colleagues, friends and disciples in a number of occasions (retirement, anniversaries of the dedicatee, of the chair, etc.).This article reconstructs how Festschriften became an academic tradition from the end of the 19th century onward, flourishing in humanities and social sciences. It is based on some thousand French and foreign examples. It describes the material organisation of these volumes and explores the nature of this academic genre. It shows that Festschriften at once answer to the needs of celebration and belong to an economy of the gift. This conclusion stresses the complexity of the intellectual field, in which gestures of generosity coexist with strategies of power and influence.