The list prepared by the selector for ordering the books can serve a further purpose: it can form the basis of a catalogue to accompany the exhibition. If the audience is going to be a very general one, no catalogue may be needed: the books themselves may be sufficient. But a more specialised audience – chemists or teachers, football players or geologists – will almost certainly want to read or refer to some of the books they see at the exhibition, and they will be grateful if they can pick up a catalogue of the books on display and take it away with them.