Being quite a fan of the design work in Alien, when I saw this going cheaply I decided to pick it up. So, yes, Giger. Main influences: birth, death, breasts, penises and monochromatic nightmares. It's rather Baconesque.
Sadly, it's difficult to tell if a good fraction of his work is rubbish, or the book is filled with sub-standard output. Badly-drawn sketches of alien genitalia (while I'm sure they give vital insight into the artist's mind *cough*) are not my idea of fun. It's quite a disappointment, really, since his best output is breathtaking (see Alien again), and some of it (like my personal favourite, New York City XIII) isn't particularly horrific in itself.
He has got the hang of commercial stuff. There, he can turn down the 'freaky' enough to make his work useable. For example, I hadn't realised that some of Aphex Twin's Windowlicker video was down to him. However, a book's worth of his dystopian views, with plenty of dross and less-focused work... I think I'll stick to the fluffy stuff for a while.