Presents and discusses the various reliability aspects of modern instrumentation systems for industrial processes, with special emphasis given to the influence of human behaviour on systems reliability. Subject areas covered include: the mathematical tools available to assess the reliability of instrumentation systems, their applications and limitations; the way in which theory is put into practice during the design of equipment; the quality control aspects of both hardware and software, and the availability of integrated systems in the field as compared with the design criteria. Actual data, test criteria and maintenance strategies are also included.