It is with a heavy heart that we join many colleagues in remembering a groundbreaking researcher in the field of logic, deduction and knowledge representation and reasoning, Prof. Steffen Hölldobler. Prof. Hölldobler passed away in May 2023. He will be remembered for his many research contributions, e.g., his seminal work on equational logic programming, his work on weak completion semantics and his forward-looking work on neuro-symbolic integration. Please see this webpage for more information.