Collectors played an essential yet misunderstood role in the success of Impressionism. Even though they were not immune to economic and social woes, they were often engaged in defending this artistic movement that they had helped come to life, establish itself or make known, each according to their times. It is this group of committed collectors that the present work seeks to examine. From assembling a collection to donating it 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 20th 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 16 international specialists. Depeaux, De Nittis, the Palmers, O'Hara, Buhrle, 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.