József Tari started to collect miniature books 45 years ago. His miniature library now holds more than 5000 tomes. The smallest book in his collection is just 2.9 x 3.2 millimeters in size. This is much larger than the smallest books ever created (like that one, made by Russian scientist in 2016), but still very impressive.
The video is in Hungarian. However, it still allows to marvel at craftsmanship of creators of the books.
You can find more info at József’s web site: http://jozsef-tari.webs.com/. If you’d like to start your own miniature book collection, there also is a miniature book exchange there.