Seven-time Grammy nominated European band Tangerine Dream is a singular phenomenon. As an instrumental band using only high-end modern technology, yet surrounded by a strong rock 'n' roll identity, it is hard to put a label on them. Many have tried to copy what has become "The Tangerine Dream Sound" - so far without success. Originally released on CD in 2013, "The Castle" is based on a Franz Kafka story and is the latest in a series of albums whose music is based on the works of great authors (after Edgar Allan Poe, Gustav Meyrink, and James Joyce). There's a hidden secret behind this unfinished Franz Kafka story - "The Castle" was never meant to be a building as one might assume. Kafka goes further, much further. The story pursues a deeper study of humanity and society and is perhaps one of Tangerine Dream's most ambitious projects. In the words of the late Edgar Froese, "It is impossible to turn "The Castle" into music. That's why it will never be more than an incomplete and aborted attempt. If we fail, the risk is at least worth the applause." It is up to each individual to judge whether the album can capture the spirit of the original and the band can live up to its challenge.