Constraint logic programming, the notion of computing with partial information, is becoming recognized as a way of dramatically improving on the current generation of programming languages. This collection presents the best of current work on all aspects of constraint logic programming languages, from theory through language implementation. Beginning in the mid-1980s constraint logic programming became a powerful and essential theoretical concept whose first practical application was the development of efficient programming languages based on Prolog. Benhamou and Colmerauer have taken care to illustrate the strong links between current research and existing CLP languages. The first part of the book focuses on significant theoretical studies that propose general models for constraint programming, and the two following parts develop current ideas on themes derived from these languages (numerical constraints, Booleans, and other finite domains). The concluding part on CLP language design gathers work on original constraints and on top-level implementation.