This book contains papers which investigate how to extend logic programming toward the artificial intelligence and software engineering areas, covering both theoretical and practical aspects. Some papers investigate topics such as abductive reasoning and negation. Some works discuss how to enhance the expressive power of logic programming by introducing constraints, sets, and integration with functional programming. Other papers deal with the structuring of knowledge into modules, taxonomies, and objects, withthe aim of extending logic programming toward software engineering applications. A section is devoted to papers concentrating on proof theory and inspired by Gentzen-style sequent or natural deduction systems. Topics such as concurrency are considered to enhance the expressive power of logic languages. Finally, some papers mainly concernimplementation techniques for some of these logic programming extensions.