The seven-volume proceedings set LNAI 16631-16637 constitutes the refereed proceedings of the 19th International Conference on Knowledge Science, Engineering and Management, KSEM 2026, held in Beijing, China, during July 17–19, 2026. The 186 regular papers and 99 special track papers included in these proceedings were carefully reviewed and selected from 695 submissions. These papers have been organized in the following topical sections: Volume 1: Knowledge Science with Learning and AI Volume 2: Knowledge Engineering Research and Applications Volume 3: Knowledge Management Volume 4: Optimization and Security for big knowledge Volume 5: Science Volume 6: Engineering Volume 7: Management