You can't buy Julian Assange's new book at Barnes & Noble. Or through Amazon.com. And he probably wouldn't be all that pleased if you "liked" it on Facebook, either. In "Cypherpunks: Freedom and the Future of the Internet," Mr. Assange and three of his acolytes—Jacob Appelbaum, Andy Müller-Maguhn and Jérémie Zimmermann—warn us that the Internet, once a "platonic realm," is now under attack not just from the state but also from corporations like Google and Facebook