No one would - or nearly no one would build - purposefully build a tool to experience boredom. But if you created something (like a book) with a purpose (like exploring the multiverse) and let it rest trapped in a reinforced magic vault for some time (think of plate tectonics completely changing the world's surface)... well, who could blame anything to get a little bored?
The book isn't the only of It's kind and not the first of its kind to leave, but eventually, it does so. Some of the more conservative artifacts give feeble protests, talking about the colony of mold that have grown on them might evolve into intelligent life. It wouldn't even take that long. The book is unmoved. He finds a suitable master to bond with and then a suitable universe to explore...