"But who is Bluewright?"
"He may not be a real person; but he can't be without meaning. There's something behind that name."— The Witch, ch. VII
After Devil's Tor, Lindsay began work on his last novel, The Witch. This was never finished. Chapters 1 to 19 were published by the Chicago Review Press in 1976.
The witch of the title is a woman called Urda, who lives in a mysterious and perhaps magical house on the Sussex Downs. A man, Ragnar, is invited to the house and is given a vision of the soul's experiences after death.
More detailed plot summary here.