The poster acquired the category of art at the end of the nineteenth century in Europe and later in the United States. Major museums and private institutions in this latter country and in Germany, France and Great Britain began to collect them. In Spain, the most important collector at the century was the young Catalan named Luis Plandiura.There are, at present, three collections of posters on Picasso which are considered the most important, comprising originals produced by him and reproductions of his works. Two of these collections are in Germany and one is in Spain. The former belong respectively to Dr. Fritz Lempert and to the Museum at Heidenheim and der Brenz. The first is characterized by the fact that it contains the oldest posters, has several prints of original posters for the same exhibition and, moreover, possesses the largest number of posters reproducing works by Picasso. That of the Heidenheim Museum is mainly famous for having copies of the fifty-five posters which Christoph Czwiklitzer has classifies as original works by Picasso.Volumes 1and 2 contain six hundred and thirty posters in chronological order, including those referring to permanent exhibitions and of unspecified date at the end. The posters are reproduced one to a page, with the technical data about each one shown on the facing page so that the reader has both the poster and its details available at the same time. At the end of Volume 2, we include Lists of Dates, Works and Persons and Institutions mentioned in Volumes 1 and 2.In Volume 3, the six hundred and thirty posters are organized for commentary on the basis of sixty-three topics (Life, Self-portraits, Sculpture of Right Hand and Photographs of Picasso, Jose Ruiz Blasco, Landscapes, Engravings, Madeleine and Alice Princet, Theatre, Ballet and Dance, Guernica, Dora Maar, etc.). In this way, the reader can appreciate different versions, styles and works in which Picasso dealt with the same theme during the different periods of his life.Volume 4 provides information, organized by theme and within each theme by the number of the poster in Volumes 1 and 2, regarding the quotations, notes and bibliography on the posters, illustrations and specific information used in the article of Volume 3. This format has been adopted in order to facilitate uninterrupted reading.