Want to own a book? Buy a hard copy. Amazon, Apple, Google, B&N eBooks are only licensed.
From a paper written by Nathan Savage Libraries, eBooks & Copyright Law we read:
Kindle: License Agreement and Terms of Use Digital Content is licensed, not sold, to you by the Content Provider. This statement effectively strips away all of the rights libraries and others would be granted as the owners of information resources, and so they will not be able to “sell, rent, lease, distribute, broadcast, sublicense, or otherwise assign any rights to the digital content or any portion of it to any third party”
In addition to not owning Amazon’s “digital content,” those who license the content from Amazon will be limited to viewing it “solely on the [Kindle] device or as authorized by Amazon as part of the service,” which is to say that content from Amazon will only be viewable on a Kindle, or in one of the Amazon-created applications made for computers, cell phones, etc.
Barnes & Noble, Sony and Google have similar restrictions explained in the article. Digital rights management software does a good job in protecting the rights of the publishers, unfortunately user rights have somehow a lower priority.