Do you write in your books? Highlight? Make notes? Or do you like to keep your copies as pristine as possible?

Good god no. I like to keep my copies as pristine as possible, unless I have multiple copies of it, but even then very rarely. I just don’t like to deface books, but in the past I have done so in books that I have bought when I was at college, and when I was a kid, but nowadays I wouldn’t dream of it.