Copyright date or publication date, which one should I cite? Can't believe I've got to the end of my PhD before asking this one! I want to cite a work whose copyright date is 1996 but whose first paperback edition (the one I'm referencing) is 1999. Which date is correct?
I have actually asked a librarian about this issue as it came up for me in the past.

She told me to cite the exact copy that I am reading. If what you are reading is the first paperback edition (usually the inside left initial pages will have information about this), then do cite that.