The two volume set LNAI 15778 and LNAI 15779 constitutes the refereed proceedings of the 19th International Conference on Augmented Cognition, AC 2025, held as part of the 27th HCI International Conference, HCII 2025, which took place in Gothenburg, Sweden, June 22–27, 2025.The total of 1430 papers and 355 posters included in the HCII 2025 proceedings was carefully reviewed and selected from 7972 submissions.The papers have been organized in topical sections as follows: Part I: Neurotechnology and eye tracking in augmented cognition; augmented cognitiona dn user experience;Part II: Emotions in augmented cognition; enhancing learning and memory.