This dictionary owes its success to its rigor, its ease of use, and the originality of its approach. Like many compilation works of this kind, it does not define simply for the sake of definition: it identifies the basic meaning(s) of concepts by citing the phrases in which they are formulated and the key texts that "clarify" them. Thus, it takes into account the fertility and richness of concepts. The reader will not find here a hasty stock of mummified knowledge, but rather an essential tool for an authentic practice of philosophy. Each term is presented according to the various fields in which it appears (epistemology, ethics, psychoanalysis, etc.); the bibliographies make it possible to complement and deepen the research. A philosophical concept takes its meaning from philosophers—this is the premise on which this work is based. This dictionary of philosophy contains the basic concepts, from the most traditional to the most contemporary, that are essential for understanding philosophical thought. Its originality lies in the process of giving philosophers the floor to define the terms they use, whether the great classical concepts or those they invent. Therefore, terms will be defined primarily through quotations from the authors, thus establishing a specific dynamic in their history. This dictionary also makes room, on the one hand, for original concepts and vocabulary borrowed from philosophy and other disciplines upon which philosophy feeds (psychoanalysis, sociology, linguistics, and anthropology), and, on the other hand, for contemporary thinkers who create and renew philosophical thinking by grounding it in our contemporary era.