During a silly moment a couple of years back I thought about making a bicycle mounted book carrier.
Basically I often ride to a nearish park and do a few circuits.
I usually stop for a short break at the half way point and it's really quite nice sitting in the summer sun watching the wildlife,
what I really needed was my current book to read.
My 82 Holdsworth Avanti is my least special bike so it got the carrying a bike lock mod - adapter plate that mounts on the bottle screws.
It seemed to me that that lock is about the same dimensions as a book and I did almost finished the book carrier.
Unfortunately my better bikes don't have bottle screws, but there are band-on alternatives ....