Barriers to the effective search and exploration of large document databases

that adjacency has some meaning as it does in physical space. However, unlike LC, the "dimensions" that make up this space must themselves be meaningful to all users on an a priori basis. I believe that the issue of the nature of this space is the single most important and, unfortunately, most difficult, issue facing the coherent design (and subsequent evaluation) of digital information and communication systems. I do have some ideas and some research that begins to address the problem of developing content organization "dimensions" which can be represented to users as a coherent space that should require little, if any, training for users to be able to navigate through it.