H.R Giger

In 1979, picking up the late H.R. Giger's book Necronomicon in the original Forbidden Planet shop in Dean Street was a challenge . 
This was heady stuff. Dark and disturbing visions that were seared into your brain .
 I didn't pick up the book to browse through too often. At that time it was just  too far out there  for me. Just when i needed a jolt as to how far out there an artist of Giger's genius  could push it.
Even with a quantum leap in Special effects 
Its hard to imagine any film on the horizon that packs the punch Alien did on its release.

Original Designs for the Alien creature by Ron Cobb based on Dan O'Bannon's descriptions

After O'Bannon showed Ridley Scott Giger's Book .There's only one way it could go.
Disturbing.different and totally Alien to say the least.