Article is pretty cool, and the book itself is amazing. The book is Codex Seraphianus, by Luigi Serafini, to save some of you a click. Apparently there is a new 40th anniversary edition with a few new pictures out now, but I think if you have an older edition you are fine.
I bought a used copy through AbeBooks (a book finding service) in the late 1990's after hungering after it for years. It cost $300 used back then, which seemed insane, but I've never regretted it. Some years later another edition came out for $150 or so, which is a downright bargain. I don't know if that one is still available.
AbeBooks still sends me about 1 notice per week 20+ years later whenever another copy becomes available. I could of course click the link to get them to stop, but receiving them makes me smile even though I have a procmail rule directing them to a special folder that I only look at occasionally. In internet terms, it seems like an unreal amount of time.