This book constitutes the refereed proceedings of the 9th International Conference on Web
Reasoning and Rule Systems RR 2015 held in Berlin Germany in August 2015. The 5 full papers
4 technical communications presented together with 4 invited talks were carefully reviewed and
selected from 16 submissions. The scale and the heterogenous nature of web data poses many
challenges and turns basic tasks such as query answering and data transformations into complex
reasoning problems. Rule-based systems have found many applications in this area. The RR
conference welcomes original research from all areas of Web Reasoning and Rule Systems. Topics
of particular interest are: answer set programming complex events datalog description logics
event-condition-action rules information extraction and logic programming.
