This one is for my daughter's bike and I have one higher up on the shelf supports for my bike. I have my air compressor and a few bike tweak things stored close at hand. It works screwed into a horizontal or vertical surface as long as the strap is snug. This would probably work on a sturdy bookshelf if you were an apartment dweller that just needed to balance your bike more securely.
I got my double sided Velcro from an electronics / networking supply. It is very handy for hiding your computer wires under your desk, too.