My apologies to the original designer for not giving due credit – I was just shown this image out of context from a friend who saw it in Copenhagen. Leave a source in the comments if you know.

My two bits:

Make the central hole eccentric from the outer diameter. That way your books need not all be the same height. Also, it would add a little dynamic interest to the piece. Put some cushioning in the I.D. and you have a great reading spot!