Does anyone know if I can sell my Kindle books back to Amazon? Can't find anything to tell me yes or no. Thanks,

I don't think so. Seems that you buy a digital copy of something that is basically nothing to them - a digital copy needs no shipping, no paper, nothing concrete to them. So why would they "buy" it back? They gain nothing at all from that whatsoever. The lack of ability for you to read it again? That's not a pressing issue.

There seems to be a "return for refund" period after you buy a Kindle book, but it must not last long. I've only had, so far, one cancelled sale that I noticed. I think that if the period for a refund were longer I would have seen more cancelled sales....