In case you haven't heard of this odd book: http://en.wikipedia.org/wiki/Voynich_manuscript
My Wild Mass Guessing
? The book has a language no one can decipher because the grammar developed in another universe, and the plant illustrations do not match any known species of this world because they are from another one.
Also, this foldout page seems to depict nine worlds connected by wormholes:
What is interesting about that number is that in Norse mythology and Northern European folktales in general there are supposedly Nine Realms, and that sometimes we get visitors to our world from these realms, including the Aelthar - elves. The Aelthar of Norse myth are said to resemble humans (like the nubile females depicted bathing), and that sometimes they would kidnap human children and replace them with changelings.
Perhaps the elves WERE in fact visiting us, and that their attempts to communicate with us included child-swapping. And perhaps following the start of the witch trials the elves decided to leave Midgard (Earth) behind, and in their haste one of their scientists left behind his field diary, the so-called Voynich manuscript.
Or maybe in a world without internet someone would be bored enough to waste hours and hours coming up with a nonsensical language and grammar and writing a book in said language, complete with meticulous illustrations of strange creatures and patterns.