Codex Seraphinianus is an incredible book - there is no arguing that. Unless you argue that it's not a book at all - but a glimpse into an invented, surreal art world that puts Harry Potter, Dr. Suess, and The Hobbit to shame.
The book is Codex Seraphinianus and the author is an Italian artist and architect - Luigi Serafini - who created an entire fake code language and made an enormous encyclopedia-type book with illustrations and writing - but all the writing is in a language that is complete and utter gibberish.
In essence, it is an unreadable book. A book written - handwritten at that - yet not meant to be read.
There have been entire lectures, research studies, and college classrooms that have tried to decipher the handwritten script and fabricated pages, yet its meaning is inconclusive, and the author maintains there is no sense to be made of it.
I suppose you can derive meaning out of it with a little creativity, but better yet, it can inspire creativity beyond its hardbound cover.
If you like anything to do with codes it is a must "read". And some of the most bizarrely beautiful pieces of art lie inside as well - it is almost too weird for a book, but not for the Internet :)
Read more about the weirdest book ever "written" here:
https://www.abebooks.com/books/rarebooks/serafini-fantasy-art-weird/Codex-Seraphinianus.shtml