Invited Talk -- A Guide for Manual Construction of Difference-List Procedures -- Constraints -- Linear Weighted-Task-Sum - Scheduling Prioritized Tasks on a Single Resource -- Efficient Edge-Finding on Unary Resources with Optional Activities -- Encoding of Planning Problems and Their Optimizations in Linear Logic -- Constraint-Based Timetabling System for the German University in Cairo -- Databases and Data Mining -- Squash: A Tool for Analyzing, Tuning and Refactoring Relational Database Applications -- Relational Models for Tabling Logic Programs in a Database -- Integrating XQuery and Logic Programming -- Causal Subgroup Analysis for Detecting Confounding -- Using Declarative Specifications of Domain Knowledge for Descriptive Data Mining -- Extensions of Logic Programming -- Integrating Temporal Annotations in a Modular Logic Language -- Visual Generalized Rule Programming Model for Prolog with Hybrid Operators -- The Kiel Curry System KiCS -- Narrowing for First Order Functional Logic Programs with Call-Time Choice Semantics -- Java Type Unification with Wildcards -- System Demonstrations -- Testing Relativised Uniform Equivalence under Answer-Set Projection in the System cc??? -- spock: A Debugging Support Tool for Logic Programs under the Answer-Set Semantics.

This volume constitutes the thoroughly refereed post-conference proceedings of the 17th International Conference on Applications of Declarative Programming and Knowledge Management, INAP 2007, and the 21st Workshop on Logic Programming, WLP 2007, held in Würzburg, Germany, during October 4-6, 2007. The 16 thoroughly revised full papers presented together with 1 invited paper were carefully reviewed and selected from numerous submissions. The topics covered are constraints; databases and data mining; extensions of logic programming; and system demonstrations.