Max Beckmann (1884-1950) is the most prominent German painter of the first half of the twentieth century. Following the publication of his diaries and letters as well as the catalogues raisonnes of his paintings, drawings, prints, and colored works on paper, a complete catalogue of his fifty-four sketchbooks is now being made available for the first time. Beckmann used these largely unpublished sketchbooks, which span the period between 1899 and his death in 1950, throughout his entire active career. The more than 1,300 pages and nearly one hundred, now single sheets that have been linked to the individual sketchbooks are all illustrated, documented, and annotated. An introduction to each sketchbook elucidates its themes and composition. This catalogue raisonne presents new information about Beckmann's working method and provides unique insight into his thoughts as a painter. The analysis and publication of the sketchbooks closes a large gap in the study of Beckmann's oeuvre.