The Zentrum Paul Klee’s scientific documentation has been built up by the Paul-Klee-Stiftung (Paul Klee Foundation – PKS) since the 1970s with the participation of the Klee family, and is unique in its kind for an artist of Classical Modernism.

The scientific documentation comprises several thousand copies of Paul and Lily Klee’s correspondence with artist friends, art dealers, collectors and museums. The documentation of works provides illustrations of and information material on virtually all of Klee's 9,800 works. An extensive photographic documentation on the life of Paul Klee comprises personal photographs as well as historical photos of friends and colleagues, of places where Klee lived, and his exhibitions. The photo collection runs from ca. 1880 to the present, and is continually being added to. A press-book documentation contains newspaper articles and reviews on the 600 or so individual and group exhibitions that took place during Klee’s lifetime.

Finally the documentation on some 800 forgeries represents a special collection within this archive. It was compiled over many years in connection with expertises and declarations of authenticity, which were previously carried out by the Paul-Klee-Stiftung and now by the Zentrum Paul Klee as the only institution worldwide authorised to do so.