This text deals comprehensively with important aspects of artificial intelligence and expert systems. It illustrates the knowledge system approach and emphasises the relevant use of such knowledge in specific systems. A considerable portion of the text is devoted to the subject of knowledge representation, including methods of dealing with uncertain, incomplete and vague knowledge e.g. methods related to non monotonic logics and commonsense reasoning.The book is divided into five parts related to a detailed analysis of knowledge Introduction to Artificial Intelligence, Knowledge Representation Knowledge Organisation and Manipulation, Perception Communi cation and Expert Systems and Knowledge Acquisition.