What are some good ways to display or store books by taking up the least amount of room possible?

What are some good ways to display or store books by taking up the least amount of room possible?

Hey guys, I've been a lurker for awhile now and now that I'm home for the summer I'd like to (or rather need to) revamp my room. I have way too much stuff. What are some good ways to display or store books by taking up the least amount of room possible?
Cosmos

Cosmos

obligatory picture post

obligatory picture post

Plant ID Needed Please!

Plant ID Needed Please!

Mom’s Sculpture Garden

Mom’s Sculpture Garden

another mystery

another mystery

Color Help!

Color Help!