The Mask of Mephisto

I read this many years ago when it was part of a double novel hardback along with Murder By Magic. I really don't remember much but I do like this cover. Not for it being part of The Shadow's canon as it doesn't really have anything in common with the great covers of the golden age but simply as an illustration. If you haven't read this or, like me, read it and can't really recall the story check this out.