"The problem of directing a user to stored information, some of which may be unknown to him, is the problem of "information retrieval"… In information retrieval, the addressee or receiver rather than the sender is the active party. Other differences are that communication is temporal from one epoch to a later epoch in time, though possibly at the same point in space; communication is in all cases unidirectional; the sender cannot know the particular message that will be of later use to the receiver and must send all possible messages; the message is digitally representable; a "channel" is the physical document left in storage which contains the message; and there is no channel noise because all messages are presumed to be completely accessible to the receiver. The technical goal is finding in minimum time those messages of interest to the receiver, where the receiver has available a selective device with a finite digital scanning rate."

“An information retrieval system will tend not to be used whenever it is more painful and troublesome for a customer to have information than for him not to have it... Where an information retrieval system tends not to be used, a more capable information retrieval system may tend to be used even less.”

“Information retrieval is the name for the process or method whereby a prospective user of information is able to convert his need for information into an actual list of citations to documents in storage containing information useful to him. It is the finding or discovery process with respect to stored information. It is another, more general, name for the production of a demand bibliography. Information retrieval embraces the intellectual aspects of the description of information and its specification for search, and also whatever systems, technique, or machines that are employed to carry out the operation. Information retrieval is crucial to documentation and organization of knowledge.”

“The requirements of information retrieval, of finding information whose location or very existence is a priori unknown.”

“People will resist information unless the price of not knowing it greatly exceeds the price of learning it.”