Human-Computer Interaction (HCI) is undergoing a profound epistemological shift. For decades, the field has developed a rich repertoire of research methods informed by its interdisciplinary origins. These methods have enabled HCI researchers to explore phenomena across a wide range of domains—from desktop work environments to everyday life—with approaches that span controlled experiments, ethnographic fieldwork, and design interventions. However, the increasing integration of artificial intelligence (AI), and particularly generative AI (genAI), into both interactive systems and research workflows is disrupting the foundational assumptions behind these methods. This Dagstuhl Seminar invites participants to examine how HCI research methods must adapt in light of these developments—and what new opportunities and risks this transformation entails.