Invited Talks -- P 6= P: Why Some Reasoning Problems are More Tractable Than Others -- Semantic Technologies in Selected Industrial Applications -- Web Reasoning for Cultural Heritage -- Full Papers -- Planning with Transaction Logic -- A Generalization of Approximation Fixpoint Theory and Application -- Query Answering over Contextualized RDF/OWL Knowledge with For all-Existential Bridge Rules: Attaining Decidability using Acyclicity -- Exchange-Repairs: Managing Inconsistency in Data Exchange -- Rules and Ontology Based Data Access -- Technical Communications -- Semantic Search for Earth Observation Products using Ontology Services -- Airport Context Analytics -- Navigating among Educational Resources in the Web of Linked Data -- Investigating Information Diffusion in a Multi-Social-Network Scenario via Answer Set Programming -- Web Stream Reasoning Using Probabilistic Answer Set Programming -- Federated Debugging of Lightweight Ontologies -- Revisiting the Hardness of Query Answering in Expressive Description Logics -- An Ontology for Container Terminal Operations -- Posters -- Ontology-Based Answer Extraction Method -- Collective, Incremental Ontology Alignment Through Query Translation -- Disjunctive Constraints in RDF and Their Application to Context Schemas -- Linked Open Data in the Earth Observation Domain: the Vision of Project LEO -- Combining Fuzzy and Probabilistic Reasoning for Crowd-Sourced Categorization and Tagging -- Doctoral Consortium -- Visual Editor for Answer Set Programming: Preliminary Report -- Adaptive Stream Query Processing Approach for Linked Stream Data: Extended Abstract.-Combining Logic and Business Rule Systems.

This book constitutes the refereed proceedings of the 8th International Conference on Web Reasoning and Rule Systems, RR 2014, held in Athens, Greece in September 2014. The 9 full papers, 9 technical communications  and 5 poster presentations presented together with 3 invited talks, 3 doctoral consortial papers were carefully reviewed and selected from 33 submissions. The conference covers a wide range of the following: semantic Web, rule and ontology languages, and related logics, reasoning, querying, searching and optimization, incompleteness, inconsistency and uncertainty, non-monotonic, common sense, and closed-world reasoning for the web, dynamic information, stream reasoning and complex event processing, decision making, planning, and intelligent agents, machine learning, knowledge extraction and information retrieval, data management, data integration and reasoning on the web of data, ontology-based data access, system descriptions, applications and experiences.