The sketches, for the most part difficult to decipher, were made by Beethoven as part of the compositional process. They are considered characteristic of his working method. Thousands of very different sketchleaves have survived, very few of which have previously been fully reconstructed. They are an ideal source as they shed light on the genesis of plans and works. Reconstructing, editing and making facsimiles of the Beethoven sketches is one of the Beethoven-Archiv's tasks (sketch edition).