As a member of my generation, I hardly ever take books out of the library. Coddled by the internet, I tend to conduct research using online journals and other such resources conveniently accessed from my bed or desk. However, I was still raised under the influence of my grandfather, and thus I hold books in their physical manifestation with an odd sort of reverence. Books are great and wonderful things, and should be treated as such. I remember being a little horrified at the concept of marking one's page by folding it over when it was first shown to me, but that was nothing compared to the abject revulsion of seeing hordes of university students take pens, pencils, and highlighters to the pages of their textbooks. While I recognize some people have their own study system in which highlighter and pencil play an integral role, I have never learned to appreciate such a system and find the presence of externally imposed markings on the pages of a book to be extremely distracting to the point of detracting from the actual content of the text. Thus, I have taken a live and let live approach. When I see students highlighting the pages of their books, I do not run over and tear the markers out of their hand and scold them. It is their book. However, all of that changes when it is a library book. Damn it, if it is a library book, that means many more people expect to read this book when you are done with it! If you absolutely must mark up the pages, make a photocopy and highlight that.
As those reading this might have guessed, I picked up a book from the library the other day. After a mind numbing couple of hours solving linear algebra problems, I decided on a whim to grab a book on the Crimean War. So I found the section, spotted three copies of a book that looked interesting, and every single one of them was full of highlighter and scribbled notes in the margins. It was horrible. I took the one that looked the least abused, but I still haven't brought myself to read it. So my message is this: if you are one of those people who insists on marking the pages you read when studying or writing a paper, find some way around doing it to a library book. That library book is not yours, and someday some student who is obsessive-compulsive about books is going to come along and be driven insane by your handiwork. It's neither nice nor pleasant.