Collectors played an essential yet misunderstood role in the success of Impressionism. Though not immune to economic and social woes, they were often engaged in the defence of this artistic movement that they had helped come to life, establish or make known, each in their own time. It is this group of committed collectors that the present work seeks to examine. From the "making" of a collection to its donating to a museum, from supporting artists within the borders of France to publicising the movement internationally, from the first intimate private showings to the questions raised by the presentation of these works in museums, collectors were present at every stage of the development of Impressionism, from the dawn of the movement to the middle of the twentieth century. This volume aims to re-examine and reassess the importance of these collectors in the political, social and economic contexts of their times through the contributions of sixteen international specialists. Depeaux, De Nittis, the Palmers, O'hara, Bührle, Caillebotte, Fayet: whether they are the subjects of dedicated case studies or part of a broader discourse, the multiplicity of profiles of these collectors and the paths they followed will allow readers to gain a better understanding of their importance in the history of the Impressionist movement.