Looks nice mate! I’m no woodworking guru but I would suggest that you evaluate the wall/screw fixings and the possibility of the wood bowing carefully. Books etc can be very heavy, and if the wall screws and fixings pull out things will get ugly.

There are a couple of websites I’ve seen that let you calculate the bow of a span of a given material over a certain length, search up a couple and figure out what weight you want the shelves to take.

That’s a beauty!

Neal Asher is a sci-fi favourite of mine.