This is not an item that I am accustomed to posting, but I got an email about it over 12 hours ago . . . I don't see it posted anywhere; it if has been, please accept my apologies and know that the duplication was not intentional.
The Tor.Com eBook "club" free selection (May 9 to 15) is A Fire Upon the Deep by Vernor Vinge. Amazon ratings are fine--4.1 (524), but they really shine at GoodReads--4.35 (474).
You have to register in order to get into the "club," and to receive this freebie, and the ones to come, but it's just email address and country that they ask for.
It looks like you can get the ebook in either mobi and ePub, and perhaps both.
Try using
the webpage with this URL. If that doesn't work, I'm sure that
http://www.tor.com will.
Please do not take this post to mean that I have had a conversion experience, in which I now embrace science fiction, or even just fiction in general. I am still a hard core unbeliever.