Design for augmented reality and the gestural interface is currently an intriguing but undefined space. Shengzhi Wu, an AR designer at Google AR team, dives deep into those challenging design questions and shares his insights on his two-year research of designing and prototyping AR concepts. It includes controlling IoT devices with gestures, applying the theories of affordances into AR interface design, and more. This book is also a part of his Master Thesis project at Carnegie Mellon University, the School of Design. His prototype demos from this book received over one million exposure on Twitter and ignited many discourses in the XR community.