The extensive works of Alkan – though there are no symphonies, operas or songs to bring him to a deservedly wider audience – were admired by Busoni, Rachmaninov and Egon Petri, all of whom played his music. Alkan wrote just three chamber works, which all make great demands of the performers and contribute significantly to the development of the form. Take, for example, the slow movement, L’enfer (‘Hell’) of Alkan’s Grand Duo concertante where the extreme closely spaced dissonances offer an unprecedented vision of the darkest abyss.