I know how that goes! A couple of semesters ago, shortly before my class went over a section in the textbook, a court handed down a ruling that changed a chunk of the chapter. I have to make sure I keep up with what's going on in the world.
And now I have to step away from the computer again and try to put more things away. Unfortunately, I seem to make an even bigger mess by the time I'm finished!
I used accounting textbooks for doorstops and stepladders (my roommate was 4’10”). You couldn’t resell them!