Maria Fischer's "Traumgedanken" book is a collection of "literary, philosophical, psychological and scientifical texts" about dreams. The book uses threads pierced through the pages and affixed to other pages to make physical hyperlinks between ideas.
On five pages there are illustrations made out of thread. Their shape and colour relies on the key words on the opposite page. This way an abstract image of the dream about dreaming is generated.
In addition there are five pages where a significant excerpt from a text of the opposite page is stitched into the paper. It is not legible because the type's actual surface is inside the folded page. This expresses the mysteriousness of dreams and the aspect of dream interpretation.
(Thanks, Michael Chabon!)