 A pre-release version was only available via internet at the Tangerine Dream's website in March 2004.The album includes a studio version of a live performance at the Royal Festival Hall, in London, on March 6th, 2004.The show was the opening night of the Ether Electronic Music Festival followed by the world premiere of a restored version of the Italian silent movie “Purgatorio” from 1911 by Giuseppe de Liguoro's, based on the second part of Dante Alighieri’s “"Divine Comedy"”

Purgatorio is the second album of a trilogy consisting of the following albums all inspired by Dante's work