Do free speech rights apply against private actors? Free Speech Theory challenges contemporary thought on this issue. It champions free speech not for its contribution to epistemic advance or informed democratic participation, but as a product of individuality, located in a system of freedom from state control. This has wide-ranging implications for rights-claims directed against private actors concerning online, workplace, and public-interest based forms of speech. This innovative, rigorously researched, and comprehensive restatement of free speech principle is both topical and important. It has significance for policy makers, practitioners, and commentators around the world.