These present a full repertoire of training types of articulation and textures, but clearly go beyond this strictly practical task. They are lyrical miniatures in which technical performance formulae, given depth and sophistication, have become a means of musical expression. Critical source-edition edited by Jan Ekier and Paweł Kamiński based on manuscripts, copies approved by Chopin himself, and first editions. Its purpose is to present the works of Chopin in authentic form.