If you're an Amazon Kindle for iOS app user, Amazon is warning you to avoid their latest update. Kelly Hodgkins from TUAW writes:
Apparently, a glitch in the update is erasing the user's entire book library from their iOS device.
Ouch. Since Amazon stores copies of every Kindle book you buy on the cloud, this is likely more annoying than annihilating, but it would absolutely interrupt your ability to keep reading on your iOS device, short term. Amazon is obviously aware of the issue, so a fix should be on its way. Until then, if you haven't updated already, stay clear.