This book examines design as a mode of philosophical inquiry, proposing that design gains critical relevance when it engages the material and technological structures that shape everyday life. Rather than offering solutions, it foregrounds design as a practice of questioning--one that reframes problems, visualizes tensions, and materializes ideas to make them thinkable. Through this lens, design becomes a method of understanding the world rather than transforming it through predetermined visions. The book argues that the real power of design lies in developing tools: tools that construct alternative worlds for reflection, and tools that help us perceive the existing world anew. In doing so, it positions design as an intellectual practice capable of expanding both our conceptual and material horizons. Design as a practice of questioning Tools to reflect and understand New Volume within BIRD series.