You can read it for free or download it as a PDF. You don't get to keep it forever (the PDF will self-destruct in thirty days) but it's an excellent offering nonetheless.
I mean, I could go off on a tangent about how self-destructing PDFs is an example of "tethered appliances" taking over the Internet and taking away our control over what content we can access. Then I could casually mention Jonathan Zittrain's The Future of the Internet--And How to Stop It. But I won't.