A large advertising sign hangs outside the new British Library building on Euston Road in London. It reads ‘Step Inside. Knowledge Freely Available’. 1 A good slogan, but what does it imply about the way knowledge is thought of in contemporary society? Obviously the Library is a repository for a huge number of books, recordings, manuscripts and so forth. One would have to say that it is these that are freely available (and it is wonderful that they are of course). But in what sense are they knowledge? Or rather why it is that the advertisers decide to promise, by the emphasis of that term, something already a value, already more than the papers and inks themselves: something people can take away as ‘knowledge’?