As the first monograph in the field, this state-of-the-art survey provides a rigorous presentation of logic programs as representational and reasoning tools. The authors used this book successfully as a text for a MSc course. The use of logic programming for various types of reasoning, particularly for nonmonotonic reasoning, is thoroughly investigated and illustrated and a variety of knowledge representation formalisms, like default negation, integrity constraints, default rules, etc., are treated in depth. Besides the main text, detailed introductory background and motivational information is included together with a bibliography listing 215 entries as well as the listing of the Prolog interpreter used in the text for running numerous examples.