The first of four planned books of different versions (version with a second piano, version with a string quartet, version with orchestra) of the E minor Concerto. The concerto takes a classical form in a version adapted through a generation of pianist-virtuosi into a concerto in the style brillant, the development of which Chopin closed. There are variations to be found in the written text. The variations marked ossia were marked in this way by Chopin himself or written in his hand into his students copies; variations without this definition are derived from the context of the text in original versions or from inability to gain a singular interpretation of the text.