The LNCS journal Transactions on Large-scale Data and Knowledge-centered Systemsfocuses on data management, knowledge discovery, and knowledge processing, which are core and hot topics in computer science. Since the 1990s, the Internet has become the maindriving force behind application development in all domains. An increase in the demand forresource sharing across different sites connected through networks has led to an evolution ofdata- and knowledge-management systems from centralized systems to decentralized systemsenabling large-scale distributed applications providing high scalability. This, the 56th issue of Transactions on Large-Scale Data- and Knowledge-Centered Systems,contains five fully revised and extended papers selected from the 39th conference on DataManagement - Principles, Technologies and Applications, BDA 2023. The topics cover awide range of timely data management research topics on adaptive learning, personal datamanagement systems, topic discovery in large corpora, spatio-temporal query processing, anddata generation.