Sue Curry Jansen's book Censorship: The Knot that Binds Knowledge and Power was published in 1988. I only discovered it several years later, and was immediately impressed. Normally, censorship is thought of as a government restriction on information, for example in dictatorships or during wartime. Therefore, most of the concerns expressed about censorship - including condemnations, justifications and discussions - are about governments. Sue took a broader view, seeing corporate power as a key driver of censorship: keeping some sorts of information confidential can serve the interests of corporations, and likewise certain sorts of knowledge claims are threatening to them. Corporate leaders want to control narratives about themselves and their products.