One of the most basic concepts underlying the practice of organizing and representing information is that it requires making choices. The organization and representation of information, choosing what to present, and how to arrange it is an ideological act, and even to a degree a political act. Guides, indexes, directories, databases, classification systems, and other methods of providing access to information and establishing “bibliographic control” are designed with particular goals in mind, and exist because of particular reasons, affordances, biases and prejudices. And, in turn, being aware of these goals and reasons, and of the effects that they have on information sources, services and tools, is a major component of information literacy, of being an effective user of information and a successful researcher.