Of late, expert system is the biggest single use technique amongst the artificial intelligence techniques. An expert system is an artificial intelligent programme incorporating a knowledge base, an inference engine and the user interface. Whether it is in medicine, Mineral exploration, evaluation of chemical structure or in industrial applications, expert system has established its wider role and applicability as far as expert decisions are concerned. The biggest flexibility of an expert system is that, it permits a non-expert to do the work of an expert. The aim of this paper is to consolidate the various steps and methodologies for the development, operation and application of expert system for problem solving and in industrial applications.