I'm anal-retentive to the point that I keep a log of dates of when I've finished reading books. It doesn't help that I take a long time, since I'm always reading a couple simultaneously besides my stash of magazines. Perhaps the trick is to keep a log of dates of when I've started reading a book, so to coax myself to finish the earlier ones first. You know, adopt a FIFO approach. However, I think my oldest backlog is Salman Rushdie's Satanic Verses, which I've started about 4-5 years ago. It'll be quite challenging to find that book to continue reading, not to say remember where I've stopped after all these years.