After reviewing the historical development of libraries and catalogues -- indexes -- the evolution of secondary or abstracting services is discussed in the light of the rapidly growing rate of publication of new research literature. The retention of traditional formats and indexing practices is shown to have had an adverse effect on the benefits computerization of abstracting services might have brought. Users of such services have to contend with a multiplicity of systems which makes maximum utilization difficult. In spite of the large volume of abstracts published, evidence is presented to indicate that only a relatively small proportion of literature is currently reported in secondary services. Rejecting a possible model for a global information system, it is argued that addition of citation indexing to secondary services would offer a means of screening the literature for the "valuable" publications. After discussing the utilization of literature in increasing the knowledge domain of users and the influence of user habits in using knowledge in decision-making, possible future developments in information systems are outlined.