When possible, I only buy used books (and I do my best to avoid buying them on Amazon)

Books are meant to be read. You’re supposed to bend them, dog ear the pages, and write in the margins. That’s what I love about buy used books. I get to see the meta-story of the book itself.

I own a copy of Crime and Punishment that’s seen more than its fair share of wear and tear. The back cover has a water stain, the pages feel worn, and the spine is bent. Its pages have been written in, there are notes in the margins, and passages have been marked and underlined.
But that’s what I love about this copy. I love seeing what others felt was important to write down. What others felt was important enough to stop reading and grab a pen. (Anecdotally, I don’t myself as “reading” a book unless I have a pen in hand and am taking notes, but that’s just me personally)

Another example is my copy of Al-Muqaddimah (The Introduction) by the scholar Ibn Khaldun. Ibn Khaldun wrote this work in 1377. Most of the contents aren’t very relevant now, but that’s not why I love it. Ibn Khaldun is considered to be the father of sociology and it’s the meta-thesis around his mindset and way of thinking that I find so fascinating.
Some poor grad student read it and covered it nearly head to toe in notes (presumably for some sociology or history class). His writings about social cohesion (عصبيّة) and the rise and fall of civilizations may seem basic now (especially with how we think about the Roman Empire) but the methodologies with how he came to those conclusions are fascinating. And, personally, I wouldn’t have made those leaps if not for the notes from this previous owner.