Let's not forget this really basic tip... to safely snap the cover back onto the Reader, place the reader face down on a flat surface to distribute the force, and then press the cover onto the back of the Reader until it's all snapped in. You don't want to accidentally damage the screen if you put a finger in the wrong place.
And NatCh... your tip on holding the mark button down is the best! I had forgotten about that, and was lamenting the difficulty in switching between multiple books when I'm reading more than one. This makes it really easy! (I wish it was so easy to continue even without a bookmark!) I like sometimes to have several going at once.. a classic book (like from the Harvard Classics) that's great literature but takes effort to read, another book that's educational or useful, a Christian book to inspire me, and what I read most -- something fun like a novel!