What can you say about a book consisting of 360 pages of fantastic, surreal, hand-drawn illustrations (not unlike Hieronymous Bosch) of a completely alien world, accompanied by pages and pages of indecipherable script, written in an imaginary language (entirely invented by the author), using unique numerical systems unlike any other in the world? The author of this book, an Italian designer named Luigi Serafini, spent 18 months obsessively creating this work between 1976 and 1978. Thirty years later, large parts of the book remain untranslated, because the alien dialect to has defied attempts to translate it into any known language. No one knows what the book is really about, but it appears to be a fictional encyclopedia describing an alien world, written in the language of its inhabitants.
Several years ago, a group of cryptographers managed to decipher some of the "numbers" used in the Codex, and they found that it was in a base 21 numerical system! The lettering remains untranslated to the present day, however.
The obsession that went into the creation of the Codex Seraphinianus suggests that Luigi may have been mentally unstable, not unlike Vincent Van Gogh. This book is available as a very expensive, oversized book (often available with coffee table-sized art books), though it has also been scanned and made available online from various sources.
Two links about the Codex that are well worth pursing: