If you look closely at the photo above you will see that the shelf is coming apart and that the photo album beneath that shelf is holding up the books. (this is a repair that needs attention SOON)
Years ago a friend was visiting our home for the first time and she stepped into the library/art studio combo and quickly stepped out. I had told her upon entry that the shelves in this room are deep and that in some instances there are 2-3 rows of books on each shelf. She looked at me and said "Do you have any idea how much this room must weigh?" Honestly I had never given that a thought. But my husband assures me that the floor boards are stout and well built and that this room will not one day end up our bedroom in the basement (which is also book lined).
When my now, 20 year old nephew, was about 7 he was visiting and was fascinated by all the books in every room in our house (since that was several years ago you can well imagine that there are many, many, many more books housed there now). He sat on our bed (which is basically a bed surrounded on all sides by books) and his eyes surveyed the room and he quietly inquired "Your Mom let you do this....." I smiled and said yes, he asked me to convince his Mom (my sister) to allow him to do the same. He was visiting this summer and informed me that he has my DNA and I told him I hoped so. He laughed and said "no, Aunt Deb I have it all, because one day I want a little house like this filled with books, art, plants and aquariums." (we no longer have aquariums because I needed the room for books)