Expert and knowledge-based systems have great potential for industrial control systems, particularly in the process industries. Recognising the importance of this emerging area, the Institution of Electrical Engineers organised a Vacation School on the subject, for engineers from industry and academia, at the University of Strathclyde in September 1990. The course and this resulting text cover four main issues: the background of knowledge-based control, artificial intelligence, applications of knowledge expertise, and deductive control. The background material presents knowledge based control from the perspective of Systems Engineering and Information Technology. When combined with an introduction to both artificial intelligence and fuzzy logic, a firm foundation is laid for consolidation of the later material of the book. The importance of fuzzy control is considered and the use of expert systems in self-tuning control is discussed. The use of real-time knowledged based systems in Fermentation supervisory control is described and the impact of neural networks in process modelling is also considered. The development of COGSYS which is an environment for building expert systems and its applications is described, together with its application to a gas processing plant. Case studies in condition monitoring are presented. The development of qualitative models for physical systems which is currently attracting considerable interest from the Al community is considered. The design of multivariable control systems and other aspects of process control are also covered.