THE SEVEN AGES OF INFORMATION RETRIEVAL

Vannevar Bush's 1945 article set a goal of fast access to the contents of the world's libraries which looks like it will be achieved by 2010, sixty-five years later. Thus, its history is comparable to that of a person. Information retrieval had its schoolboy phase of research in the 1950s and early 1960s; it then struggled for adoption in the 1970s but has, in the 1980s and 1990s, reached acceptance as free-text search systems are used routinely. The tension between statistical and intellectual content analysis seemed to be moving towards purelyg statistical methods; now, on the Web, manual linking is coming back. As we have learned how to handle text, information retrieval is moving on, to projects in sound and image retrieval, along with electronic provision of much of what is now in libraries. We can look forward to completion of Bush's dream, within a single lifespan.