This particular piece has made the rounds of the blogs over the past few days, so you might have seen it already. But most of the blogs I read got it wrong.
Most of the descriptions referred to this as an example of analog hyperlinking, but that's not really what Maria Fischer was trying to do. The threads in this book don't reflect the factual relationship that you'd expect with hyperlinks. Instead, these threads reflect a dream about dreaming.
To ease the access to the elusive topic, the book is designed as a model of a dream about dreaming. Analogue to a dream, where pieces of reality are assembled to build a story, it brings different text excerpts together. They are connected by threads which tie in with certain key words. The threads visualise the confusion and fragileness of dreams.
If you'd like to see more examples of books turned into art, check out the Books as Art page.