The film is based on a book by Jean Ray (Raymundus Joannes de Kremer), though I haven't read the book.
I checked the status of the DVD and it is still available from Cinematek, which is like the Belgium equivalent of BFI, I got my copy from their cinema shop. (actually that link shows quite a few titles I wouldn't mind owning, I wonder if they post to the UK).
Hard to find on DVD, I got my copy over in Belgium and its a 2 disc edition with the Cannes version and the Director's version, both in excellent shape. Both versions are worth watching but I prefer the Cannes version as its in English and the trims do not damage the story despite what the director thinks, [Harry Kümel, he of Daughters Of Darkness fame]. Susan Hampshire plays 3 or 4 parts at the same time.
ReviewIn a huge decrepit house somewhere in another time, another place, a dying old man gathers a strange collection of people to hear his will and final judgement. The people shall be rich but they must never leave Malpertuis forever. I cannot say any more without spoiling the plot, lest to say this is one of the strangest and most intriguing arthouse films you are ever likely to see. Mystery, myth and madness, the story is pure fantasy but played straight, the ending when it comes is a bit disappointing but then you realise you've witnessed something that will stay with you for a long time.