Introduction to the 39th International Conference on Logic Programming Special Issue

This issue of TPLP contains selected papers of the 39th International Conference on Logic Programming (ICLP 2023), held at Imperial College London, UK, from July 9 to July 15, 2023. The International Conference on Logic Programming (ICLP) is the premiere international scientific venue for presenting, discussing, and disseminating fundamental and applied research in the field of logic programming and in related interdisciplinary fields. The conference was launched in 1982, with its first edition in Marseille, France, and continues to serve the broad international logic programming community. ICLP 2023 was a special edition of the conference as it celebrated also the closing event of the Year of Prolog – a year-long celebration of the 50th anniversary of the introduction of the Prolog programming language. The conference included a dedicated session to discuss the achievements accomplished throughout the year, the assignment of the 2023 Alan Colmerauer Prize, and an event on “Teaching Prolog: the Next 50 Years.”