This item is not the definitive copy. Please use the following citation when referencing this material: McKnight, C., Dillon, A. and Richardson, J. (1992) Hypermedia. In A. Kent (Ed.) Encyclopedia of Library and Information Science, Vol. 50, New York: Marcel Dekker, 226-255. Overview: The field of hypertext/hypermedia has mushroomed so much in the last five years that an article such as this cannot hope to be all-embracing. Rather, what we will do is provide a perspective on hypertext/hypermedia while offering guidance to the published literature. The perspective we give is essentially user-centred since we believe that ultimately it is user issues which will determine the success or failure of any technology. We begin with a brief introduc...