In this chapter, I outline the design research approach I employ in this book within the contexts of research through design and speculative design. To help readers understand the three case studies presented later, not as mere design projects or artistic outputs, but as research artifacts for exploring human-AI relationships, I outline how design has produced knowledge within human-computer interaction (HCI). First, I discuss how design artifacts have expanded beyond being mere containers of knowledge. They have become means for constructing new questions and opening interpretive spaces through the design process and iterative production and use. Next, it examines how design, through alternative approaches like critical, frictional, and speculative design, has positioned itself as a discursive practice that reflects on sociotechnical realities and imagines possible futures, moving beyond being merely a tool for problem-solving or improvement. Finally, to complement the limitations of design fiction, it outlines how approaches involving actual use and materiality draw imagination into experiential events and the friction of everyday life. This clearly positions the case studies presented in this book not as definitive answers, but as exploratory research that opens possibilities.