Books with Gnostic elements

I really like books/movies with gnostic themes/elements.  I've read rather a lot of them.  I can recommend some if you want.
 
 Here's one:
 
  Inverted World, By Christopher Priest
 
 
 Have you any..?

Gee clouds, what's a "gnostic element"?  Is that like the Matrix, or something?  "cause I thought that was dope.
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