You're likely referring to H.R. Giger's design work for Frank Miller's "The Dark Knight Returns" and "Sin City," but I think you might be confusing it with another project.
If you're looking for the PDF, I have some bad news: hr giger 39s necronomicon pdf verified
The Necronomicon is a fictional book of dark knowledge in H.P. Lovecraft's Cthulhu Mythos. You're likely referring to H
Here's what I could find:
The book you might be referring to seems to be: hr giger 39s necronomicon pdf verified
A fascinating topic!
The copyright laws protect H.R. Giger's work.