Dr. Harold Boley passed away in December 2020. Being a well-known scientist in the semantic web movement and the Chair of RuleML from 2001 to 2020, Harold devoted a lot of efforts to integrate the academic research in the area of rules-based knowledge representation with the commonly used rule engines. In particular, he initiated and actively pushed the integration of RuleML and DecisionCAMP and coined the name “Declarative AI” for a summit that annually brings together researchers and practitioners. This year the Declarative AI will be held in September for the first time without Harold but the Rule Challenge will carry his name. Link