Network information systems reached the public consciousness this year
as a result of the phenomenal growth in the use of the Internet. In p
articular, the software constituting NCSA (National Center for Superco
mputing Applications) Mosaic and the World Wide Web have made global h
ypermedia a widespread reality for the first time. The technology unde
rlying this software is described to explain the protocols behind info
rmation spaces. These include the historical predecessors, the current
protocols with examples, future directions for the software, and disc
ussion of research systems with different architectures. Reasons for i
ts popularity are given, with the goal of illuminating successful serv
ices for the National Information Infrastructure.