E-ink book readers are a relatively new technology. It's quite an achievement, engineering-wise, to have a device that is lightweight, holds hundreds of books, and feels more like reading a reflective paper surface than staring into a glowing computer screen. Amazon got the jump on this with their Kindle device, and immediately got greedy by applying DRM (digital restrictions) on all the books they sell. You can save Amazon e-books to your PC but you can't share them with friends and if your Kindle crashes, the books on your PC will not be recognized by the next Kindle you buy. Amazon solves this "problem" by storing all your books on their servers, and making it simple to do wireless downloads of the DRM-ed books to your new device. DRM also means you can't cut and paste from the books or edit them in any way.
Making the consumer dependent on a single company, which happens to manufacture the hardware, but has also used coercive pricing strategies to make authors feel that theirs is the "go to" publisher, is an unacceptable "locking up" of knowledge. Let's go full Godwin and say it's just a step or two from bookburning. The authors are paid when you make the purchase (theoretically), there is no need to control their ideas like this.
We went through this process in music ten years ago -- companies had DRM-ed, proprietary forms of music files. (Recall Windows' .wma file.) Now even Amazon sells mp3s. (Yes, mp3s aren't completely open source but at least you can send one to a buddy.)
So what is the French Resistance for e-book consumers? There are various means to "crack" books but short of that, the first step is to get away from Amazon's hardware.
The main open standards of e-books are non-DRM'ed files in the EPUB or MOBI formats. These can be found easily on the web; eventually there will be even more open-source books circulating.
Kindles will read MOBI but not EPUB (DRM isn't added to existing books you load, only to the books Amazon sells).
Kobo is a Canada-based company that sells an e-reader every bit as good as the Kindle. Kobo's device reads both EPUB and MOBI. The company has a bookstore that sells some non-DRMed books but mostly they use Adobe Digital Editions -- a DRMed form of EPUB. You don't have to use the bookstore, though. Mainly you want to get your hands on a non-Amazon reader, install an e-book manager such as Calibre on your computer, and start hunting for non-DRM-ed books.
The Stacks is Bruce Sterling's term for Amazon, Facebook, Google, Microsoft, and Apple. "Life Outside the Stacks" is an occasional series on taking back control from these New Gilded Age entities.