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This book constitutes the refereed proceedings of the 15th International Conference on Logic Programming and Nonmonotonic Reasoning, LPNMR 2019, held in Philadelphia, PA, USA, in June 2019.
The 22 full papers and 3 short papers presented in this volume were carefully reviewed and selected from a total of 39 submissions.
The papers were organized in topical sections named: applications; argumentation; foundations and complexity; knowledge representation and reasoning; and systems.

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Applications.- Train scheduling with hybrid ASP.- Telco Network Inventory Validation with NoHR.- An ASP-based Framework for the Manipulation of Articulated Objects using Dual-arm Robots.- C-ASP: Continuous ASP-based Reasoning over RDF Streams.- Internet Routing and Non-Monotonic Reasoning.- Argumentation.- Assessing arguments with schemes and fallacies.- Simple Contrapositive Assumption-Based Frameworks.- Argumentation-based Explanations for Answer Sets using ADF.- Foundations and Complexity .- Treewidth and Counting Projected Answer Sets.- Splitting Epistemic Logic Programs.- Founded World Views with Autoepistemic Equilibrium Logic.- Towards Dynamic Answer Set Programming over finite traces.- A Sequent-Type Calculus for Three-Valued Default Logic, or: Tweety Meets Quartum Non Datur.- Knowledge Representation and Reasoning.- Diagnosing Data Pipeline Failures Using Action Languages.- Repair-Based Degrees of Database Inconsistency.- Elect: An Inconsistency Handling Approach for Partially Preordered Lightweight Ontologies.- Elaboration Tolerant Representation of Markov Decision Process via Decision-Theoretic Extension of Action Language pBC+.- Systems.- Evaluation of disjunctive programs in WASP.- telinge = ASP + Time.- Verifying Strong Equivalence of Programs in the Input Language of GRINGO.- The return of XORRO.- Degrees of Laziness in Grounding: Effects of Lazy-Grounding Strategies on ASP Solving.- Enhancing DLV for Large-Scale Reasoning.- Pruning External Minimality Checking for ASP Using Semantic Dependencies.- Declarative local search for predicate logic.

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