# The general structural features of the system considered as a network of units of information linked to each other and to documentary items. This m… - Brian Campbell Vickery

Systems transfer or transform materials, energy or information - and usually all three. An information system is one whose prime function is to transfer or transform information: the telephone system is an obvious example. This book concentrates on certain types of information system: those concerned with the transfer of information between specialists, mainly with reference to their work, and mainly based on documents. The focus is thus on specialised documentary information systems.

User needs determine what functions should be provided, and different functions require different structures.

Information retrieval is now an accepted part of the new discipline of information science and technology... I have concentrated on the field with which I am most familiar, the problems of bibliographic description and subject analysis.