Franz Liszt

Liszt wrote more piano music than anyone else worth playing, invented the modern recital, and left a catalogue so large and so revised that identifying which version of a piece you are buying is a real problem.

Most of it is very hard. The exceptions are worth knowing: the Consolations, several of the Années de pèlerinage pieces, and the Liebesträume are within reach of a good amateur. The Hungarian Rhapsodies, the Transcendental Études and the B minor Sonata are not, and no edition marked "simplified" will make them so without removing the point.

He revised constantly and published several versions of the same work — the Transcendental Études exist in three, of increasing difficulty, and editions do not always say which. His transcriptions of other composers are a separate world again: the Schubert song transcriptions are among the finest things he wrote and are frequently catalogued under Schubert.